Southern Water: Sewage

For too long, water companies have discharged unacceptable levels of sewage into our rivers, lakes and seas.

The Government remains committed to reducing both the frequency and duration of storm overflow spills, in line with the Storm Overflows Discharge Reduction Plan (SODRP). The SODRP will eliminate ecological harm from all storm sewage discharges by 2050.

As part of Price Review 2024 (2025-30), Southern Water is investing £1.1 billion to reduce storm overflow spills by 24% by investing in 246 spill reduction schemes. As part of this cycle, 4 investigations and asset improvements are planned across the City of Southampton and a further 6 at assets that currently overflow to Southampton Water.

The Water (Special Measures) Act is introducing independent monitoring of every sewerage outlet, with water companies required to publish real-time data for all emergency overflows. Discharges will have to be reported within an hour of the initial spill. This will match the pre-existing duty for storm overflows and create an unprecedented level of transparency, enabling the public and regulators to see where, and how often, overflows are discharging, and hold water companies to account. This will meet the Government commitment to ensure monitoring of every outlet.

Furthermore, the Independent Water Commission, led by Sir Jon Cunliffe, will recommend reforms to reset the water sector. The Independent Water Commission: interim report was released on 03 June 2025. Final recommendations will be published this summer and presented to both the UK and Welsh Governments.