Question to the Department for Environment, Food and Rural Affairs:

To ask the Secretary of State for Environment, Food and Rural Affairs, what steps her Department has taken in response to spills into the Kennet, Pang, and Lambourn chalk streams from Thames Water sewage treatment works between 2021 and 2025.

The Environment Agency (EA) has led the Water Industry National Environment Programme, which sets out a wide range of improvement schemes that Thames Water must deliver, including investigations and actions to reduce discharges from storm overflows, with priority given to sensitive sites such as chalk streams.

Groundwater infiltration into the Thames Water sewer system is a leading cause for storm overflow spills in the Kennet, Lambourn and Pang catchments. The EA has required Thames Water to produce Groundwater Impacted System Management Plans to set out how the company plans to reduce groundwater infiltration.

Since April 2025, the EA has completed inspections of sewage treatment works on the Rivers Kennet, Pang and Lambourn as part of its increased programme of inspecting over 800 Thames Water wastewater assets. Any permit breaches identified are assessed on a case-by-case basis for their environmental impact. Confirmed serious permit breaches are investigated and enforced against in line with the EA’s Enforcement and Sanctions Policy.