Investment plans for storm discharge sites

We’ve been carrying out our largest ever upgrade of sewers and sewage treatment works. But we know more investment is needed across our region. That’s why we asked Ofwat for increased investment in the regulatory cycle between 2025-2030.

We’ll keep this page updated with the schedule of new schemes as detail becomes available.

You’ll also find information on when we expect to meet the government's targets for storm discharges. This is a long-term plan being delivered over the next 25 years. You’ll find more specific detail on our storm overflow reduction plan on our investing in river health page.

Please note that this list, and details within it, will change as projects progress. This page was last updated in May 2025.

*Phosphorus levels calculated on a rolling 12 month mean average.

Site names beginning with:

A

Abbess Roding

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Abbey Mills Pumping Station CSO

This CSO was connected to the Lee Tunnel following its completion in 2016. This was part of the London Tideway Improvements programme.

The Thames Tideway Tunnel connects to the Lee Tunnel at Abbey Mills in Stratford. This is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Abbeydale Road

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Abingdon

An upgrade is planned for Abingdon STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Acton Storm Relief CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This is intercepting flows that would have previously discharged to the river. The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This final stage will add to the work already undertaken to improve the health of the Thames. This will add to the positive effects on the river already achieved from the previous stages.

Find out how we're investing in river health.

Aldermaston STW

An upgrade is planned for Aldermaston STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in early 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Aldershot STW

An upgrade is planned for Aldershot STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in early 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Alicia Avenue CSO

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Allendale Road / District Road / Sudbury Heights Avenue

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Alperton Lane

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Alton STW

An upgrade is planned for Alton STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in in early 2028.

In 2024 we also completed an upgrade to the storm tanks at the local Newmans Lane Pumping Station at a cost of £10 million. This will reduce the need for untreated sewage discharges during storm conditions. The scheme is due for completion in 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning. 

See our groundwater impacted system management plan for Alton.

Amersham Balancing Tanks/Amersham Vale STK

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Ampney St Peter STW

An upgrade is being planned for Ampney St Peter. It will include a substantial increase in treatment capacity, though the design hasn't been finalised. The project is likely to complete in 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Ampney St Peter.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Anyand Park Road, Twickenham

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Andoversford

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Appleton STW

Appleton STW was upgraded in 2024 at a cost of more than £7 million. This work provides a major increase in treatment capacity, from 34 to 47.5 litres per second. This will reduce the need for untreated discharges in wet weather. We have additional work planned in 2027, which will further improve the ability to treat the volumes of incoming sewage.

We have additional work planned in 2027, which will improve the ability to treat the volumes of incoming sewage.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Arborfield STW

An upgrade is planned for Arborfield STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2030.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Arford

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Ascot STW

Ascot STW upgrade is now complete at a cost of more than £11 million. This upgrade provided a major increase in treatment capacity, from 157 to 220 litres per second. This will reduce the need for untreated discharges in wet weather. Additional work is planned and will be complete in 2027.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Ash Vale

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Aston Le Walls STW

Aston Le Walls STW has been upgraded to increase the capacity of the storm tanks at a cost of more than £0.5 million. This will reduce the need for untreated sewage discharges during storm conditions.

We're also  planning to improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Auckland Road storm tanks

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Avon Dassett

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Avondale Road

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Aylesbury STW

Aylesbury STW is being upgraded at a cost of more than £15 million. This work will improve the treatment of sludge on the site.

We're also  planning to improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2030.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

B

Bakers Farm, High Wych

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Bampton STW

An upgrade is planned for Bampton STW. This work will provide a major increase in treatment capacity, from 23 to 36 litres per second. This will reduce the need for untreated discharges in wet weather. We plan to complete this work in spring 2028.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Banbury Rd Middleton Cheney

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Banbury STW

An upgrade is planned for Banbury STW. It includes an increase in treatment capacity, from 266 to 490 litres per second. This will reduce the need for untreated discharges in wet weather. This work is forecast to complete in spring 2029.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Barbers Lane

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Barford St Michael STW 

An upgrade is planned for Barford St Michael STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus entering the river to below an average level of 3mg/l*. We plan to complete this work in summer 2025.

Barkway STW

An upgrade is planned for Barkway STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 3.5mg/l*. We plan to complete this work in autumn 2026.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Basingstoke STW

An upgrade is planned for Basingstoke STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Basingstoke.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Beckley

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Beckton STW

Beckton STW is being upgraded at a cost of £185 million. This will increase the site’s capacity for population growth by extending the existing treatment processes.

Beckton STW will receive storm water from the Thames Tideway Tunnel and the project will improve resilience of the works to treat this flow. The project also includes elements of major plant maintenance to ensure resilience and effluent quality is maintained. The majority of the scheme is due for completion in 2024. Some elements of the project will extend to 2030.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Beddington

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Beech Hall Crescent, Walthamstow

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Beenham STW

Beenham STW has been upgraded. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme completed in 2024.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Beer Lane CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Bell Wharf CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Benson STW

Benson STW has been upgraded at a cost of more than £9 million. This work provides a major increase in treatment capacity, from 58.7 to 74.9 litres per second. This will reduce the need for untreated discharges in wet weather. The work was completed in 2024.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Benson.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Bentley STW

Bentley STW has been upgraded at a cost of more than £8 million. This project has increased the capacity of the storm tanks, so reduces the need for untreated sewage discharges during storm conditions. We have also improved the quality of treated effluent by reducing phosphorus levels entering the river to below an average level of 0.9mg/l*.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Bentley.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Berkhamsted STW

Berkhamsted STW is being upgraded at a cost of more than £25 million. The upgrades comprise two schemes; the first completed in 2023 and provides a major increase in treatment capacity, from 247 to 316 litres per second. This reduces the need for untreated discharges in wet weather. The second scheme will upgrade our treatment processes to ensure higher quality of treated effluent going to the river. We expect to complete this scheme in 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Berkhamsted. 

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Bicester STW

Bicester STW has been upgraded at a cost of more than £8 million. This work provided increased treatment capacity, reducing the need for untreated discharges in wet weather. This work was completed in 2022.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Bicester.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Birchanger - Duck End

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Biscot Road CSO

We expect these locations to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Bishop Stortford STW

An upgrade is planned for Bishop Stortford STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in summer 2028.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Blackbirds STW 

An upgrade is planned for Blackbirds STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in autumn 2029.

Blacknest, Sunningdale

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Bledington

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Bletchingdon STW

An upgrade is planned for Bletchingdon STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Blind Mans Gate, Highclere

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Bloxham STW

Bloxham STW was upgraded at a cost of more than £6 million. This provided a major increase in treatment capacity, from 30.6 to 38 litres per second, reducing the need for untreated discharges in wet weather. This work completed in 2023.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Blunsdon STW

An upgrade is planned for Blunsdon STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.4mg/l*. We plan to complete this work in spring 2027.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Boddington STW

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Bookham SPS

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Bordon STW

An upgrade is planned for Bordon STW. This will improve its ability to treat the volumes of incoming sewage as well as providing a higher quality of treated effluent. This will reduce phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in autumn 2028.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Bourton on the Water STW

An upgrade is planned for Bourton on the Water STW. This work will provide a major increase in treatment capacity, from 47 to 143 litres per second. This will reduce the need for untreated discharges in wet weather. We expect the project to complete in spring 2026.

Work is also currently being carried out to reduce groundwater infiltration and other unwanted surface water entering the wastewater network in this area. This is due to complete by the end of 2025. Further investigation will continue in this area, which will help inform our long-term planning.

See our groundwater impacted system system plan for Bourton on the Water.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Box Hill

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Boxford STW 

An upgrade is planned for Boxford STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.5mg/l*. We plan to complete this work in winter 2027.

Boyne Avenue, Hendon

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Bracknell STW

An upgrade is planned for Bracknell STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2030.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Bramley

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Braughing STW 

An upgrade is planned for Braughing STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.4mg/l*. We plan to complete this work in early 2028.

Brent Cross Flyover

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Brent Valley Golf Course, LB Ealing

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Brentfield Gardens

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Brentwood (Nags Head Lane) STW

An upgrade is planned for Brentwood STW. This scheme will ensure a higher quality of treated effluent going to the river. We expect the project to complete in autumn 2027.

Brickendon STW

An upgrade is planned for Brickendon STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. We expect the project to complete in late 2026.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Bridle Close, Ewell

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Brixton and Clapham Storm Relief CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Broadwell STW

An upgrade is planned for Broadwell STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. We expect the project, which is still being designed, to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Brockham Bridge

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Brook Way, Chigwell

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Broome (Attenuation Tank)

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Bucklebury (Briff Lane)

An upgrade is planned for Bucklebury STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. We expect the project to complete in early 2026.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Briff Lane Bucklebury.

Bucknell

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Buntingford STW

Buntingford STW has been upgraded at a cost of more than £21 million. This work will provide a major increase in treatment capacity, from 40 to 48 litres per second as well as a higher quality of treated effluent going to the river. This scheme will reduce the need for untreated discharges in wet weather. The project was completed in 2024.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Burford

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Burghfield STW

An upgrade is planned for Burghfield STW. This will include an increase in treatment capacity, as well as a higher quality of treated effluent. This will reduce phosphorus levels entering the river to below an average level of 0.25mg/l*. The scheme will reduce the need for untreated discharges.

We expect the £27m project to complete in summer 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Burghfield.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Burstow STW

Burstow STW is being upgraded at a cost of more than £30 million. This will improve its ability to treat the volumes of incoming sewage and provide a higher quality of treated effluent. It will reduce phosphorus levels entering the river to below an average level of 0.3mg/l*. We expect the project to complete in early 2026.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Bushey Court, Raynes Park / Worple Road, SW19

We expect these locations to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Bute Street

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Byfield

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

C

Caddington STW

An upgrade is planned for Caddington STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in winter 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Cage End, Essex

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Camberley STW

An upgrade is planned for Camberley STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2028.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Canfield End, Little Canfield

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Canfold Wood

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Canterbury Road, Thornton Heath

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Capel

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Carlton Cres Jnc Blenheim Cres

We expect this location to meet all government targets for storm overflows by 2030 – 2035. Find out how we're investing in river health.

Carterton STW

An upgrade is planned for Carterton STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in late 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Carterton.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Cascade Road Storm Tanks, Buckhurst

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Cassington STW

An upgrade is planned for Cassington STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in late 2025.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Castle Drive

We expect this location to meet all government targets for storm overflows by 2045 – 2050. Find out how we're investing in river health.

Castle Gardens, Dorking

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Chacombe

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Chadlington

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Chalgrove STW

Chalgrove STW has been upgraded at a cost of more than £1 million. This project will increase the capacity of the storm tanks, reducing the need for untreated sewage discharges during storm conditions. The scheme is now complete.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Channelsea West Ham Lane PS

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Chapel Row (Berks)

An upgrade is planned for Chapel Row STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in summer 2026.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Chapmore End STW

Chapmore End STW has been upgraded at a cost of over £3 million. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Charlbury STW

An upgrade is planned for Charlbury STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in summer 2026.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Charlton Storm Relief CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Charlton-On-Otmoor

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Charlwood, Surrey

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Chelsea, London SW10

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Chertsey STW

Chertsey STW has been upgraded at a cost of more than £17 million. This project has increased the capacity of the storm tanks and improved its ability to treat the volumes of incoming sewage. This will reduce the need for untreated sewage discharges during storm conditions. The scheme completed in March 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Chesham STW

Chesham STW has been upgraded at a cost of more than £20 million. These projects provide a major increase in treatment capacity to 353 litres per second. This reduces the need for untreated discharges in wet weather. It will provide a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*.

The treatment capacity upgrade completed in early 2023. The effluent quality upgrade completed in early 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Chesham.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Chieveley STW

An upgrade is planned for Chieveley STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.5mg/l*. We plan to complete this work in summer 2027.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Chigwell Road / Langston Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Chigwell Road / Woodford Green

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Chingford Storm Tanks

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Chinnor STW

Chinnor STW is being upgraded at a cost of more than £14 million. This project will provide a major increase in treatment capacity, from 47 to 73.8 litres per second This will reduce the need for untreated discharges in wet weather. We expect the project to be complete in summer 2026.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Chinnor.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Chipping Norton STW

Chipping Norton STW is being upgraded at a cost of more than £5 million.This will improve its ability to treat the volumes of incoming sewage reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Chipping Warden STW

We've completed an upgrade at Chipping Warden STW. This provides more reliable and accurate information relating to untreated discharges. The scheme completed in 2024.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Chisledon Storm Tanks

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Chobham STW

Chobham STW has been upgraded at a cost of more than £19 million. This project will ensure a higher quality of treated effluent going to the river, and improve its ability to treat the volumes of incoming sewage. The project completed in March 2025.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Cholsey STW

Cholsey STW is being upgraded at a cost of more than £8 million. It includes an increase in treatment capacity from 74 to 105 litres per second and an increase in storm tank capacity. This will reduce the need for untreated discharges in wet and stormy weather. We expect the scheme to complete in summer 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Church Hanborough STW

An upgrade is planned for Church Hanborough STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Church Hill Road, Barnet

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Church Road / Somerset Road, Wimbledon

We expect Church Road to meet all government targets for storm overflows by 2030 - 2035. We expect Somerset Road to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Church Road/Brent Lodge Park (Bunny Park)

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Church Street KT13 8DP

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Church Street CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Churt

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Cirencester STW

Cirencester STW is being upgraded at a cost of more than £29 million. This project will provide a major increase in treatment capacity, from 269 to 484 litres per second. It will also include an increase in storm water volume and treatment capacity via land treatment. This will reduce the need for untreated discharges in wet weather. We expect the project to be complete in spring 2026.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Cirencester.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Clanfield STW

An upgrade is planned for Clanfield STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2028.

Work is also currently being carried out to reduce groundwater infiltration and other unwanted surface water entering the wastewater network in this area. This is due to complete by end of 2025. Further investigation will continue in this area, which will help inform our long-term planning.

See our groundwater impacted system management plan for Clanfield.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Clapham Storm Relief Sewer, London

This is one of the 54 combined sewer overflows (CSOs) discharging to the tidal River Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This final stage will add to the work already undertaken to improve the health of the Thames which is already producing a positive effect on the river.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tunnel, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2025. Find out how we're investing in river health.

Clavering STW 

An upgrade is planned for Clavering STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.3mg/l*. We plan to complete this work in summer 2028.

Clifton

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Cobham Bridge, Adj Cobham PS

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

15 Coldharbour Lane, Bushey

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Coldicote

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Colgate

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Colin Crescent, Colindale

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Combe

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Commonside

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Compton STW

An upgrade is planned for Compton STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in autumn 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Compton.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Conolly Road Hanwell

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Coppice Green, Bracknell

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Cottered STW

Cottered STW has been upgraded at a cost of more than £2 million. This project has increased the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme was completed in 2023.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Cranleigh STW

An upgrade is planned for Cranleigh STW. This will improve its ability to treat the volumes of incoming sewage as well as providing a higher quality of treated effluent going to the river. We plan to complete this work in autumn 2028.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning. 

See our groundwater impacted system management plan for Cranleigh.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Crawley STW

Crawley STW has been upgraded at a cost of more than £34 million. This has improved its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme completed in 2024.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Cricklade STW

Cricklade STW is being upgraded at a cost of more than £7 million. This project will provide a major increase in treatment capacity, from 26 to 30 litres per second, reducing the need for untreated discharges in wet weather as well as including an increase in storm tank capacity. We expect the project to complete in autumn 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Cricklewood Broadway

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Cricklewood Lane, Cricklewood (A41 Hendon Way)

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Crofton Road, Sunnydale

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Crondall STW

We've completed an upgrade at Crondall STW. This improves its ability to treat the volumes of incoming sewage. The scheme completed in 2024.

We also identified the opportunity to optimise the existing assets to improve effluent quality. We agreed the new permit in 2024.

See our groundwater impacted system management plan for Crondall.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Crooked Billet

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Cropredy STW

An upgrade is planned for Cropredy STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Crossness STW

There’s a range of complex schemes underway at Crossness STW, including work to improve its ability to treat the volumes of incoming sewage. These schemes are likely to continue until 2030.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Croughton STW 

An upgrade is planned for Croughton STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 2mg/l*. We plan to complete this work in autumn 2026.

Cuddington STW

An upgrade is planned for Cuddington STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in early 2026.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Culham STW

An upgrade is planned for Culham STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Culworth STW

An upgrade is planned for Culworth STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in early 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

D

Dagnall STW

An upgrade is planned for Dagnall STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2025.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Daintry Close

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Dallow Road Jnc Lyndhurst Road

We expect these locations to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Darkes Lane, Potters Bar

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Dartford Creek Storm

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Dartnell Park, Byfleet

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Deadmans Bridge

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Dean Oak Lane

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Deephams STW

There’s a range of complex schemes being planned at Deephams STW, including work to improve its ability to treat the volumes of incoming sewage. These schemes are likely to continue until 2030.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Deptford Creek CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Deptford Storm Relief CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river. 

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Didcot STW

An upgrade is planned for Didcot STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2028.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Dorchester STW

Dorchester STW has been upgraded at a cost of more than £2 million. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme completed in 2023.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Dorking STW

Dorking STW is being upgraded at a cost of more than £19 million. This project will increase the capacity of the storm tanks and improve its ability to treat the volumes of incoming sewage. This will reduce the need for untreated sewage discharges during storm conditions. The storm tank scheme is due for completion in autumn 2025, with further works to improve the sites ability to treat incoming flows completing in 2031.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Dorking Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Dorton STW

An upgrade is planned for Dorton STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.5mg/l*. We plan to complete this work in spring 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Draycot Foliat

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Drayton STW

An upgrade is planned for Drayton STW. This project will provide a major increase in treatment capacity, from 43.3 to 57 litres per second. An increase in storm tank capacity will reduce the need for untreated discharges in wet weather. We expect the project to complete in spring 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Dunstable Road – Beech Road / Francis Street

We expect these locations to meet all government targets for storm overflows by 2030 - 2035.

George Street – King Street / Wellington Street

We expect these locations to meet all government targets for storm overflows by 2030 - 2035.

Kingsway (near railway bridge)

We expect this location to meet all government targets for storm overflows by 2030 - 2035.

Park Street - Bailey Street / opposite Parmead (lower level weir)

We expect these locations to meet all government targets for storm overflows by 2040 - 2045.

Duntshill Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

E

Earl Pumping Station CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Earlswood (Reigate)

Upgrades are planned for Earlswood STW. These will include an increase in treatment capacity, from 340 to 400 litres per second, providing a higher quality of treated effluent going to the river. This scheme will reduce the need for untreated discharges in wet weather. We expect the projects to complete in summer 2028.

Earlswood Common, S Of Pendleton Road

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

East Garston

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

East Grafton STW

East Grafton STW  has been upgraded at a cost of more than £0.4 million. This scheme increased the capacity of the storm tanks. This reduces the need for untreated sewage discharges during storm conditions. The scheme completed in 2023.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

East Lane CSO 1

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

East Shefford STW

East Shefford STW has been upgraded at a cost of more than £12 million. This project will improve its ability to treat the volumes of incoming sewage, providing a higher quality of treated effluent. It will reduce phosphorus levels entering the river to below an average level of 0.1mg/l*. The project completed in early 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for East Shefford.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Eastcote Avenue

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Easthampstead Park STW

We've completed an upgrade at Easthampstead Park STW. This provides a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 3mg/l*. We completed this work in March 2025.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Edgware Road

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Elmcroft Avenue, Wanstead

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Elms Road CSO

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Elstead STW 

An upgrade is planned for Elstead STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 1mg/l*. We plan to complete this work in spring 2027.

Elvetham Close

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Empress Avenue

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Epping STW

An upgrade is planned for Epping STW. This scheme will ensure a higher quality of treated effluent going to the river. We plan to complete this work in autumn/winter 2028.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Epsom Storm Tanks, Longmead Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Esher STW

An upgrade is planned for Esher STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2029.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Essendon, Holywell Bridge

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Ewhurst Road, Cranleigh, Surrey

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

F

Fairfield Avenue 1

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Fairford STW

An upgrade is planned for Fairford STW. This project will provide a major increase in treatment capacity, from 37.8 to 56.8 litres per second, reducing the need for untreated discharges in wet weather. We plan to complete this work in winter 2027/28.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning. 

See our groundwater impacted system management plan for Fairford. 

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Falconbrook Pumping Station CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Falloden Court & Brookland Rise

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Faringdon STW

Faringdon STW is being upgraded to increase the capacity of the storm tanks and provide a higher quality of treated effluent going to the river. This will reduce the need for untreated sewage discharges during storm conditions. We plan to complete this work in spring 2026.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Faringdon House CSO

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Farnborough STW

An upgrade is planned for Farnborough STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Farnham STW

An upgrade is planned for Farnham STW. This scheme will ensure a higher quality of treated effluent going to the river, reducing phosphorus levels entering the river to below an average level of 0.3mg/l*. We plan to complete this work in early 2028.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Fergusson Road, Banbury

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Field End Road Storm (Harrow)

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Field End Road (East)

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Finstock STW

Finstock STW has been upgraded at a cost of over £1 million. We completed upgrades in 2023 to ensure a higher quality of treated effluent going to the river. Further upgrades completed in 2025 to increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Fleet Main CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Fleet STW

An upgrade is planned for Fleet STW. This will include an increase in treatment capacity, as well as a higher quality of treated effluent. It will reduce phosphorus levels entering the river to below an average level of 0.3mg/l*. This scheme will reduce the need for untreated discharges in wet weather. We plan to complete this work in 2030.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Folkestone Rd Tanks, East Ham

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Forest Hill STW

An upgrade is planned for Forest Hill STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Francis Road Spill

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Friday Street, Henley

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Frogmore Storm Relief (Bell Lane Creek) CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This is intercepting flows that would have previously discharged to the river. The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

Find out how we're investing in river health.

Frogmore Storm Relief (River Wandle) CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This is intercepting flows that would have previously discharged to the river. The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

Find out how we're investing in river health.

Fulmer Drive CSO (Howards Wood Drive)

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Fyfield STW

Fyfield has been upgraded at a cost of £2 million. This includes an increase in treatment capacity, providing a higher quality of treated effluent going to the river. This scheme will reduce the need for untreated discharges in wet weather. The project completed in 2023.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Fyfield.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

G

Gap Road (Cemetery)

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Garden Way

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Gascoigne Rd Storm Tanks, Beckton

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Gerrards Cross STW

An upgrade is planned for Gerrards Cross STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Godalming STW

An upgrade is planned for Godalming STW. This scheme will ensure a higher quality of treated effluent going to the river, reducing phosphorus levels entering the river to below an average level of 0.3mg/l*. We plan to complete this work in autumn 2028.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Gordon Road

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Gordon Road

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Goring

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Goswell Street CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Granville Road

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Great Bedwyn

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Greatworth STW

An upgrade is planned for Greatworth STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete by 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Greenwich Pumping Station CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Grendon Underwood STW

An upgrade is planned for Grendon Underwood STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in mid 2025.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Grosvenor Ditch CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Guildford STW

We’re constructing a new sewage treatment works for Guildford at a cost of over £160 million. The scheme is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Gun Wharf (Wapping Dock) CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

H

Haddenham STW

An upgrade is planned for Haddenham STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete by early 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Hadham Mill

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hambleden

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hammersmith Pumping Station CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Hampstead Norreys STW

An upgrade is planned for Hampstead Norreys STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2025.

Work is also currently being carried out to reduce groundwater infiltration and other unwanted surface water entering the wastewater network in this area. This is due to complete by end of 2025. Further investigation will continue in this area, which will help inform our long-term planning.

See our groundwater impacted system management plan for Hampstead Norreys. 

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hamstead Marshall

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hanger Lane

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Hannington

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Hanwell STW

Hanwell STW has been upgraded at a cost of over £1 million. The project will increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme is now complete.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Harpenden STW

An upgrade is planned for Harpenden STW. This will improve its ability to treat the volumes of incoming sewage. We plan to complete this work in spring 2028.

We’ll also deliver a scheme to provide a higher quality of treated effluent going to the river. This will reduce phosphorus levels entering the river to below an average level of 0.3mg/l*. We plan to complete this work in 2028.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Hartley Wintney STW

An upgrade is planned for Hartley Wintney STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in autumn 2027.

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Haslemere

An upgrade is planned for Haslemere STW to provide a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l *. This will complete in 2027.

We’ll also be improving its ability to treat the volumes of incoming sewage. We plan to complete this work in early 2028.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Haslemere STW CSO

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Hatfield Heath STW

An upgrade is planned for Hatfield Heath STW. This will improve its ability to treat the volumes of incoming sewage as well as providing a higher quality of treated effluent. It will reduce phosphorus levels entering the river to below an average level of 0.9mg/l*. We plan to complete this work in autumn 2027.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Hattchets Cricklade

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Heathwall Pumping Station CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Henley Road CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Henley STW

An upgrade is planned for Henley STW. This will provide a major increase in treatment capacity, from 67 to 82 litres per second. This will reduce the need for untreated discharges in wet weather. We expect the project to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Heyford STW

An upgrade is planned for Heyford STW. This will provide a major increase in treatment capacity, from 17 to 22 litres per second. This will reduce the need for untreated discharges in wet weather. We expect the project to complete in late 2025.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

High Road Loughton

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

High Road, Woodford

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

High Wycombe

We expect this location to meet all government targets for storm overflows by 2030 – 2035. Find out how we're investing in river health.

Highfield Road Jct With Brookside Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Highworth STW

An upgrade is planned for Highworth STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Highworth Eastrop

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Hillside Avenue / Kings Avenue / Princes Avenue / Worcester Crescent

We expect Hillside Avenue, Kings Avenue and Princes Avenue to meet all government targets for storm overflows by 2030 - 2035. We expect Worcester Crescent to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hockford STW

An upgrade is planned for Hockford STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.3mg/l*. We plan to complete this work in autumn 2028.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Hogsmill STW

Hogsmill STW is being upgraded to increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme is due for completion in spring 2028.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Holloway Storm Relief Sewer CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Holmwood STW

An upgrade is planned for Holmwood STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in spring 2028.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Holybourne

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Home Park Road

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Honeypot Lane

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hook Norton STW

Hook Norton STW has been upgraded at a cost of over £8 million. This project will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.4mg/l*. We will also increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme completed in 2025.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Horley (Oxon) STW

Horley (Oxon) STW has been upgraded. This improves its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme completed in 2024.

Find out how we're investing in river health.

We expect this location to meet all government targets for storm overflows by 2040 - 2045.

Horley (Surrey) STW

An upgrade is planned for Horley (Surrey) STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in early 2029.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hornton

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Horseferry Road CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Horton-Cum-Studley STW

An upgrade is planned for Horton-Cum-Studley STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Huckers Lane (Selbourne)

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hull Green (Matching)

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Hungerford STW

Hungerford STW has been upgraded at a cost of over £5 million. This project has improved its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme completed in 2023.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Hurstwood Road West

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

I

Iron Gate CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Ironsbottom (Sidlow)

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Isle of Dogs Pumping Station CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Islip STW

Islip STW has been upgraded at a cost of over £0.3 million. This scheme increased the capacity of the storm tanks. This reduces the need for untreated sewage discharges during storm conditions. The scheme was completed in 2023.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Iver (North)

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

J

Jews Row Pumping Station (Falconbrook Storm Relief) CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Jews Row Wandle Valley Storm Relief CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Jnc Frederick Street & William Street

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Joyce Green West Syphon

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

K

Kempsford

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Kendal Road, Cullingworth Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Kew Transfer

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Kilda Road

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Kimpton STW

We've completed an upgrade at Kimpton STW. This scheme ensures a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 5.5mg/l*. We completed this work in March 2025.

We expect this location to meet all government targets for storm overflows by 2030 – 2035. Find out how we're investing in river health.

Kingham

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Kings Scholars Pond CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Kings Sutton

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Kingsclere STW

An upgrade is planned for Kingsclere STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2026.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Kingsclere. 

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Kingston Bagpuize STW

Kingston Bagpuize STW is being upgraded at a cost of over £34 million. We'll increase the capacity of the storm tanks, reducing the need for untreated sewage discharges during storm conditions. Thsi will be complete by summer 2026. We’ll also be ensuring a higher quality of treated effluent going to the river. This will be complete by summer 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Kingston Main

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Kingthorpe Terrace

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Kintbury STW

Kintbury STW has been upgraded at a cost of over £2 million. This project will improve its ability to treat the volumes of incoming sewage. This will reduce the need for untreated discharges in wet weather. The scheme completed in 2023.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Knights Lane

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Knightsbridge Road, Camberley

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Knowle Lane, Cranleigh

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

L

Leaden Roding

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Leatherhead STW

An upgrade is planned for Leatherhead STW. This will provide a major increase in treatment capacity, from 250 to 320 litres per second. This will reduce the need for untreated discharges in wet weather. We expect the project to complete in autumn 2028.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Lechlade

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Outside 135 Leeside Crescent

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Leopold Road, Church Path / Longstone Ave, Drayton Road

We expect Leopold Road, Church Path to meet all government targets for storm overflows by 2030 - 2035. We expect Longstone Ave, Drayton Road to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Leverson Street

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Lewknor STW 

We've completed an upgrade for Lewknor STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 1mg/l*. We completed this work in March 2025.

Lightwater STW

An upgrade is planned for Lightwater STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2028.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Lincoln Road CSO

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Lindsay Drive, Falcon Way

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Little Compton STW

The scheme to increase the capacity of storm tanks, reducing the need for untreated sewage discharges during storm conditions, completed in 2023. A separate scheme due to complete in 2026 will also improve its ability to treat the volumes of incoming sewage.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Little Hallingbury STW

Upgrades are planned for Little Hallingbury STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in spring 2027.

Another scheme will also ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in 2029.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Little Marlow STW

An upgrade is planned for Little Marlow STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is likely to complete in 2028.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Little Marlow.

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Little Milton

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Littlemead, Ind Estate, Cranleigh

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Littlemore Low Level

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

London Bridge CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

London Road near Hatherop Lane

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

London Road, Marlborough

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Long Reach STW

An upgrade is planned for Long Reach STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Long Crendon

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Longbridge Road

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Longley Road (1), Tooting High Street

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Lots Road Pumping Station CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Low Hall Farm Storm Tanks, Walthamstow

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

(Northern) Low Level No 1 Brook Green CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Lower Cherwell Street, Banbury

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Ludgershall STW

An upgrade is planned for Ludgershall STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Luton (East Hyde) STW

An upgrade is planned for Luton (East Hyde) STW. This scheme will improve its ability to treat the volumes of incoming sewage. This ensures a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in spring 2029.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Bancroft Rugby Ground, Buckhurst Hill

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Lyon Park Avenue

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Lytton Road SSO

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

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Maidenhead STW

An upgrade is planned for Maidenhead STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2026.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Maidenhead. 

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Main Road, Sidcup

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Manor Drive Stormwater Tanks

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Manor Farm

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Manuden STW 

An upgrade is planned for Manuden STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.3mg/l*. We plan to complete this work in spring 2028.

Maple Lodge STW

Maple Lodge STW is being upgraded to ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We’ll also increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. We plan to complete this work in 2030.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Maple Lodge. 

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Mapleton Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Markenfield Road, Guildford

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Markyate STW

An upgrade is planned for Markyate STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Markyate. 

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Marlborough STW

An upgrade is planned for Marlborough STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in early 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Marlborough. 

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Marsh Gibbon STW

An upgrade is planned for Marsh Gibbon STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.9mg/l*. We plan to complete this work in summer 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning. 

See our groundwater impacted system management plan for Marsh Gibbon.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Marsh Lane Bridge, Taplow

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Marston St Lawrence SPS

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Marsworth

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Mays Lane Overflow

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Melford Road, London, E11

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Merstham STW

We've completed an upgrade for Merstham STW. This will provide a higher quality of treated effluent going to the river. We completed this work in March 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Middle Barton STW

Middle Barton STW has been upgraded at a cost of over £1 million. This project will increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme completed in spring 2025.

We're also planning to improve its ability to treat the volumes of incoming sewage. This will reduce the need for untreated discharges in wet weather. This scheme, which is still being designed, is due to complete in summer 2026.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Middleton Cheney STW

An upgrade is planned for Middleton Cheney STW. This scheme will ensure a higher quality of treated effluent going to the river. We plan to complete this work in summer 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Middleton Stoney

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Midgham

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Mill Green (Hatfield)

We've completed an upgrade for Hatfield (Mill Green) STW. This provides a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 1mg/l*.

We completed this work in March 2025.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Millbank, Crawley

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Milton-Under-Wychwood STW

An upgrade is being planned for Milton-under-Wychwood STW. This will provide a major increase in treatment capacity, to 43 litres per second, reducing the need for untreated discharges in wet weather. The project is likely to complete in summer 2026.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Milton-Under-Wychwood.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Mogden STW

There are a range of complex schemes underway at Mogden STW, including work to improve its ability to treat the volumes of incoming sewage. These schemes are likely to be ongoing until 2030.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Montrose Avenue/Blenheim Crescent

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Moreton Pinkney

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Moreton-in-Marsh

Moreton in Marsh STW is being upgraded to increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. We plan to complete this work in spring 2029.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning. 

See our groundwater impacted system management plan for Moreton in Marsh. 

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Moreton-in-Marsh (Primrose Court)

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Moreton STW 

An upgrade is planned for Moreton STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in spring 2028.

Mornington Crescent

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Mortimer STW

An upgrade has completed at Mortimer STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme completed in 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Mulberry Court, Hall Road

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

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Nags Head Lane (Brentwood)

An upgrade is planned for Brentwood STW. This scheme will ensure a higher quality of treated effluent going to the river. We plan to complete this work in our next asset planning period (2025 - 2030) and will provide more detailed information once the work schedule is confirmed.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

North East Storm Relief CSO

We expect this location to meet all government targets for storm overflows by 2025. Find out how we're investing in river health.

Near Sezincote Lodge

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Neasden Station

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Netherlands Road CSO

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

New Bedford Road, Luton

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

New Mill (Eversley Lower Common)

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Newbury STW

An upgrade is planned for Newbury STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Newmans Lane Pumping Station

Newmans Lane Pumping Station was upgraded in 2024 at a cost of over £10 million. This project has increased the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Nightingale Lane CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Norfolk Street

This is one of the 54 combined sewer overflows (CSOs) discharging to the tidal River Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This final stage will add to the work already undertaken to improve the health of the Thames which is already producing a positive effect on the river.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tunnel, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2025. Find out how we're investing in river health.

North East Storm Relief CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

North End Road CSO

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

North Weald STW

An upgrade is planned for North Weald STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in early 2028.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

North West Storm Relief CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Northleach STW

An upgrade is planned for Northleach STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Northumberland Street CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Nr Jnc Leagrave Road - Spencer Road

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Nutter Lane / Preston Drive, Wanstead

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

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Oak Hill Park CSO

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Oakentrough

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Oakley Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Ockham Road South Foul Sewer Overflow

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Ockley Road

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Old Palace Lane

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Opposite St Stephens Hall

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Outside 115 Wentworth Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Oxford STW

We're finalising plans for a major upgrade at Oxford STW, costing more than £435m. This will provide a significant increase in treatment capacity, larger storm tanks and a higher quality of treated effluent going to the river. We plan to complete this work in early 2032.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Oxford.

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

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Pangbourne STW

Pangbourne STW is being upgraded at a cost of over £3 million. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Park Town South & West, Luton

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Passfield

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Pauls Pier CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Pavilion in Roxbourne Park

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Pease Pottage

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Penwith Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Peterborough Road 1

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Pinkham Way Storm Sewage O/F, London

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Portsmouth Road, Uxbridge Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Princes Risborough STW

An upgrade is planned for Princes Risborough STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Princes Risborough. 

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Priory Lane Storm, Mortlake

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Priory Road, Dartford (Foul)

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Prospect Road, Woodford

We expect this location to meet all government targets for storm overflows by 2030 - 2035.

Puller Road/Calvert Road Storm, Barnet

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Purton STW

An upgrade is planned for Purton STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Putney Bridge CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Q

Queen Street CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

R

Ramsbury STW

An upgrade has completed at Ramsbury STW. This has provided a major increase in treatment capacity, from 27 to 53 litres per second. This will reduce the need for untreated discharges in wet weather. The project completed in 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Ramsbury. 

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Ranelagh CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Ratcliffe Highway Limekiln CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Ratley

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Ray Lodge Road (Ray Park 1)

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Reading STW

An upgrade is planned for Reading STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2028.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Reading. 

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Reading, Blakes Lock

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Reading, Caversham

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Redbridge Lane West, Wanstead

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Regent Street

This is one of the 54 combined sewer overflows (CSOs) discharging to the tidal River Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This final stage will add to the work already undertaken to improve the health of the Thames which is already producing a positive effect on the river.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tunnel, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Ripley STW

An upgrade is planned for Ripley STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in summer 2030.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

River Lane

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Riverside STW

An upgrade is planned for Riverside STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2031.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Road A217, Burgh Heath

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Road A3, Roehampton Vale

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Roding Valley

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Rotherwick

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Rous Road, Buckhurst Hill

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Rowsham

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Ruislip Road East

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Rusper

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Rye Meads

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

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Salfords, Surrey

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Sandhurst STW

An upgrade is planned for Sandhurst STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2025.

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Savoy Street CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Selborne STW

An upgrade is planned for Selbourne STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Sevenhampton Village

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Shabbington STW

Shabbington STW has been upgraded at a cost of over £1 million. This will improve its ability to treat the volumes of incoming sewage and to increase the capacity of the storm tanks. This will reduce the need for untreated discharges in wet weather. The scheme is now complete.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Shad Pumping Station CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Shamley Green STW

An upgrade is planned for Shamley Green STW to improve its ability to treat the volumes of incoming sewage. This will provide a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.7mg/l*. We plan to complete this work in summer 2028.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Sherfield-On-Loddon STW

An upgrade is planned for Sherfield-on-Loddon STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Shotteswell

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Shrivenham

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Shutford STW

An upgrade is planned for Shutford STW to improve its ability to treat the volumes of incoming sewage. This will provide a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.4mg/l*. We plan to complete this work in winter 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Silchester STW

An upgrade is planned for Silchester STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is expected to complete in 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Silchester. 

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Slough STW

Upgrades are planned for Slough STW. These will include an increase in treatment capacity, from 1150 to 1416 litres a second. This will provide a higher quality of treated effluent going to the river. This scheme will reduce the need for untreated discharges in wet weather. We plan to complete this work in summer 2029.

We expect this location to meet all government targets for storm overflows by 2035 - 2040.

Find out how we're investing in river health.

Smith Street

This is one of the 54 combined sewer overflows (CSOs) discharging to the tidal River Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This final stage will add to the work already undertaken to improve the health of the Thames which is already producing a positive effect on the river.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tunnel, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Sonning Common STW

An upgrade is planned for Sonning Common STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

South Ealing Road, W5

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

South Lane, Ash

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

South Leigh STW

An upgrade is planned for South Leigh STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 2mg/l*. We plan to complete this work in summer 2025.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

South Moreton STW

An upgrade is planned for South Moreton STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

South Norwood

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

South Park, Ilford

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

South West Storm Relief CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Spooks Hill, North Holmwood

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

SSO, Junction Crane Valley/Bathroadse

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

St Andrews Road, Black Horse Lane

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

St Jamess Road

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

St Pauls Avenue CSO

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Stag Lane CSO

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Stamford Brook Storm Relief CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Standlake

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Standon STW

An upgrade is planned for Standon STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.4mg/l*. We plan to complete this work in autumn 2027.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Stanford in the Vale STW

Stanford in the Vale STW has been upgraded at a cost of over £4 million. This project increased the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme completed in spring 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Stanford Rivers STW

An upgrade is planned for Stanford Rivers STW. This scheme will ensure a higher quality of treated effluent going to the river. We plan to complete this work in spring 2029.

Stansted Airport

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Stansted Mountfitchet STW

An upgrade is planned for Stansted Mountfitchett STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in early 2028.

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

Stanton Fitzwarren STW

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Stanton Harcourt STW

An upgrade is planned for Stanton Harcourt STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.6mg/l*. We plan to complete this work in 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Stewkley STW

An upgrade is planned for Stewkley STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Stoke Road, Cobham

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Stone STW

Stone STW has been upgraded at a cost of over £1 million. This will increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme completed in March 2025.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Stonebridge Brook

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Stonebridge SSO, Brockham

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Streatham & Balham Storm Relief

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Streatham Storm Relief

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Streatham Vale Storm Relief

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Sunnyside Road

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Swains Road

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Swindon (Rodbourne)

Two upgrades are planned at Swindon STW to improve the ability to treat incoming flows, and increase the capacity of the sludge stream, which will improve efficiency at the works. The schemes are due for completion in 2027 and 2030.

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

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Tackley

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Takeley - Garnets

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Takeley STW

An upgrade is planned for Takeley STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.9mg/l*. We plan to complete this work in spring 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Taylors Crescent, Cranleigh

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Temple Place Essex Street

This is one of the 54 combined sewer overflows (CSOs) discharging to the tidal River Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This final stage will add to the work already undertaken to improve the health of the Thames which is already producing a positive effect on the river.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tunnel, depending on the weather.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Tetsworth STW

An upgrade is planned for Tetsworth STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.4mg/l*. We plan to complete this work in summer 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Thame STW

An upgrade is planned for Thame STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2028.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

The Broadway (Ray Park 2)

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

The Willows, North Hinksey Lane

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Therfield STW

Therfield STW is being upgraded to increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme will also ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.4mg/l*. We plan to complete this work in spring 2027.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Theydon Bois STW

An upgrade is planned for Theydon Bois STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in spring 2027.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Thornwood STW

An upgrade is planned for Thornwood STW. This will improve its ability to treat the volumes of incoming sewage as well as providing a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in autumn 2027.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Thrale Roade

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Tideway CSO (offline)

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Tonstall Road

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Tree Tops, Norbury

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Tring

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Trumpers Way, W7

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Trumps Green

We expect this location to meet all government targets for storm overflows by 2030 - 2045. Find out how we're investing in river health.

Tubney SPS

We expect this location to meet all government targets for storm overflows by 2035 - 2040. Find out how we're investing in river health.

U

Uffington STW

An upgrade is planned for Uffington STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Uffington.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

V

Vauxhall Motors

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Victoria CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

W

Waddesdon STW

An upgrade is planned for Waddesdon STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.5mg/l*. We plan to complete this work in autumn 2026.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Wanborough STW

An upgrade is planned for Wanborough STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2025.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Wantage

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Wardington

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Wargrave STW

An upgrade is planned for Wargrave STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Warmington STW

An upgrade is planned for Warmington STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Wash Water STW

An upgrade is planned for Wash Water STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Wash Water.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Water End

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Waterloo Crescent Outfall, Wokingham

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Watery Lane, Startops End

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Watlington STW

Upgrades are planned for Watlington STW to increase treatment capacity to 60 litres per second. We’ll also be providing a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.6mg/l*. This scheme will reduce the need for untreated discharges in wet weather. We plan to complete this work in spring 2027.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning. 

See our groundwater impacted system management plan for Watlington.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Waverley Lane

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Wealdbridge, North Weald

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

West End, Essendon

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

West Heath, Ramsdell

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

West Putney Storm Relief CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This is intercepting flows that would have previously discharged to the river. The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This final stage will add to the work already undertaken to improve the health of the Thames. The work has already produced a positive effect on the river.

Find out how we're investing in river health.

West Way, Botley (Syphon)

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Western Pumping Station CSO

This combined sewer overflow (CSO) is now connected to the London Tideway Tunnels system. This means it's intercepting flows that would have previously discharged to river.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Western Way

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Weston (Herts) STW

An upgrade is planned for Weston STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.4mg/l*. We plan to complete this work in spring 2028.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Weston Park

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Weston-On-The-Green SPS

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Weston-On-The-Green STW

An upgrade is planned for Weston-On-The-Green STW. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.8mg/l*. We plan to complete this work in spring 2027.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Westway Close

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Weybridge

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Wheathampstead

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Wheatley

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

White Roding STW

White Roding STW has been upgraded at a cost of over £2 million. We increased the capacity of the storm tanks to reduce the need for untreated sewage discharges during storm conditions. The scheme completed in 2025.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

White Waltham

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Whitwell STW

An upgrade is planned for Whitwell STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme is due to complete in late 2025.

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Widford and Wareside

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Wildernesse, Shoreham

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Willingale STW

Willingale STW has been upgraded at a cost of over £2 million. This scheme increases the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. This scheme was completed in early 2023.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Wimbledon Hill Road / Wimbledon Hill Wimbledon

We expect these locations to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Windsor STW

An upgrade is planned for Windsor STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2027.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Wingrave STW

An upgrade is planned for Wingrave STW to improve its ability to treat the volumes of incoming sewage. This scheme will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.7mg/l*. We plan to complete this work in late 2025.

We expect this location to meet all government targets for storm overflows by 2025 - 2030. Find out how we're investing in river health.

Winterbourne

We expect this location to meet all government targets for storm overflows by 2030. Find out how we're investing in river health.

Wisley STW

An upgrade is planned for Wisley STW. This scheme will ensure a higher quality of treated effluent reducing phosphorus levels entering the river to below an average level of 0.25mg/l.*. This will improve its ability to treat the volumes of incoming sewage. We plan to complete this work in Summer 2028.

Witney STW

Witney STW is being upgraded at a cost of more than £16 million. This work will provide a major increase in treatment capacity, from 240 to 399 litres per second. This will reduce the need for untreated discharges in wet weather. This work is expected to complete in autumn 2025.

We're also investigating the impact of groundwater on the sewer network in this area. This will help inform our long-term planning.

See our groundwater impacted system management plan for Witney. 

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Woking STW

Woking STW is being upgraded to increase the capacity of the storm tanks. This will reduce the need for untreated sewage discharges during storm conditions. The scheme will also ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.25mg/l*. We plan to complete this work in summer 2028.

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Wokingham (Ash Ridge) STW

An upgrade is planned for Wokingham STW. This will improve its ability to treat the volumes of incoming sewage, reducing the need for untreated discharges in wet weather. The scheme, which is still being designed, is due to complete in 2026.

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.

Wood Street CSO

This CSO is not directly connected to the Thames Tideway Tunnel route. However the tunnel will influence this CSO and reduce the number of discharges to the Tidal Thames.

The Thames Tideway Tunnel is the third and final stage of a program to improve the quality of the Tidal Thames. This will add to the positive effects on the river already achieved from the previous stages.

In an average year, 95% of the total volume of storm flows discharged to the Tidal Thames will be captured by the tideway improvements programme, depending on the weather.

Find out how we're investing in river health.

Woodford Halse

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Woodstock STW

We completed a project at Woodstock STW to provide more reliable and accurate information relating to untreated discharges. This was completed in 2023.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Woodstock Road Oxford

We expect this location to meet all government targets for storm overflows by 2045 - 2050. Find out how we're investing in river health.

Worminghall STW

Worminghall STW has been upgraded at a cost of over £7 million. This will ensure a higher quality of treated effluent, reducing phosphorus levels entering the river to below an average level of 0.5mg/l*. The project completed in spring 2025.

We expect this location to meet all government targets for storm overflows by 2040 - 2045. Find out how we're investing in river health.

Wynters Brook, Hastingwood

We expect this location to meet all government targets for storm overflows by 2030 - 2035. Find out how we're investing in river health.