Heath Lake SSSI restoration

We’re improving the environment at Heath Lake near Crowthorne. This site is a protected Site of Special Scientific Interest (SSSI). The only naturally acidic lake in Berkshire, it supports rare wildlife and sensitive habitats.

Our work aims to improve water quality and protect the lake for future generations. This also supports national efforts to enhance local water environments.

When and where we'll be working

Start date: 8 December 2025
End date: 31 December 2027
Location: Heath Lake, RG45 6TU
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Working hours:

Monday to Friday: 8am to 5pm
Saturday: 8am to 4pm
Sunday (reinstatement only): 8am to 1pm
Some night-time deliveries may be needed

How this may affect you

While we aim to minimise disruption, you may notice:

An increase in construction vehicles and noise during desilting and drainage works. Noise will be controlled to remain within standard limits
Some footpaths around the lake will be temporarily closed for safety. We’ll signpost alternative routes and always maintain emergency access
Traffic management will be in place on New Wokingham Road during the project:
- Northbound lane closed: 30 March to 23 May 2026
- Southbound lane closed: 26 May to 15 August 2026
- Temporary 50‑metre closures for crane operations and large deliveries on 7 May, 11 May, 16 June and 14 July 2026
- Three‑way traffic lights in use (reduced to two‑way when possible)
Parking impacts are expected to be minimal with no formal suspensions planned

What we're doing

Environmental improvements include:

Removing silt from the lake and sediment basin to enhance water clarity and support healthier habitats
Installing six new silt-capture units on road drains that lead into the lake. This will help stop future sediment build-up
Improving access paths and maintenance areas for easier future care of the lake
Conducting ecological, tree, and water-quality surveys throughout the project
Completing targeted tree works in agreement with Natural England and Wokingham Borough Council. This will allow more sunlight to reach the water and reduce leaf build-up

Protecting the environment

Heath Lake hosts rare plants like six‑stamened waterwort and lesser pondweed. It’s also home to delicate wildlife, including the trumpet ramshorn snail. Surveys show over 130 plant species, showcasing the lake’s rich biodiversity.

Our goals are to:

Improve water quality by reducing sediment and nutrients
Support the recovery of key lake and wetland plants
Strengthen the long-term health of this unique acidic lake
Protect sensitive habitats during construction

We’ll use strict environmental safeguards. This includes low-noise equipment, careful timing for vegetation work, and ongoing ecological monitoring.

Working with the community

We’re partnering with:

Wokingham Borough Council
Wokingham Without Parish Council
Natural England
Environment Agency
Friends of Heath Lake
Local residents, schools and environmental groups
Our delivery partner M Group (Morrison Water Services)

We’ll continue to share updates and work closely with local organisations throughout the project.

Get in touch

If you have any questions, please call us on 0800 316 9800 or you can email us. Please quote reference: BB01002858.

If you need extra support, you can register for Priority Services.

Our delivery partner is M Group (Morrison Water Services). Site teams will wear Thames Water-branded clothing for easy identification.

We’ll keep this page updated with the latest information.