Top of main content

Thames Water invests £93.1 million to secure Guildford’s water supply

Monday 20th November 2023 11:00

A Thames Water engineer standing next to a Thames Water van

  • Thames Water is investing over £93 million to ensure future secure water supply for its Guildford customers.  
  • This includes multi-million-pound upgrades at its Shalford, Netley Mill, Ladymead and Mousehill  water treatment sites. 
  • In 2024 work will also begin to build a new 9km water transfer pipeline which will keep taps flowing for 9,000 homes.

Thames Water is carrying out several multi-million-pound upgrades across the Guildford area to ensure a safe and secure water supply for its customers. The area currently operates as an ‘island’ water supply zone, supplied directly from nearby reservoirs and water treatment works.  

This creates challenges if there are issues onsite and means there isn’t a back-up supply for its customers. To build greater resilience the company is upgrading sites and building new infrastructure to address this challenge.  

In early 2024, work will begin to build a new 9km water pipeline, which will transfer up to 14 megalitres of water per day, equivalent to almost six Olympic swimming pools, between Pewley Reservoir in West Guildford to Netley Mills water treatment works in East Guildford. 

The project is expected to complete in time for winter 2025 and will provide greater resilience against supply interruptions for around 9,000 homes in East Guildford.  

Currently, East Guilford is supplied by a single source at the Netley Mill water treatment works. The new pipeline will ensure East Guildford benefits from a back-up source, helping prevent future supply interruptions across the local area. 

Paul Wetton, Director of Water for Thames Valley and the Home Counties, Thames Water said: “We’re committed to providing a secure and reliable water supply to all our customers, especially those in Guildford who have been impacted by recent water outages.  

“As part of our strategy to turnaround our business and deliver better for our customers we are investing over £93million to build resilience across the area and keep the taps flowing for our customers, starting with a new 9km water transfer pipe between west and east Guildford.  

“We’re inviting customers and communities to find out more about the planned water transfer pipe and are hosting two events this week.” 


Come to the community events to discover more about Guildford’s West to East transfer pipe:  

  • Thursday 23 November: St Marys Church, 59 Quarry Street, Guildford, GU1 3UA (4pm to 8pm) 
  • Saturday 25 November: Chilworth Village Hall, New Road, Chilworth, GU4 8LZ (11:30am to 5pm)  


This investment forms part of Thames Water’s wider plans to improve infrastructure across Guildford, including upgrades to water treatment sites at Netley Mill, Shalford, Mousehill and Lady Mead.  

The upgrades will reduce supply interruptions and make the sites more resilient. Investment at Mousehill water treatment works will also increase the amount of water available. The total amount invested spans both the current and next business period, which run-in five-year cycles.