United Utilities reported 388 total pollution incidents from its sewerage and water supply assets in 2025, the third-highest count among English water and sewerage companies, according to the Environment Agency's assessment published on October 29, 2026. Only Thames Water (464) and Anglian Water (433) reported more, and United Utilities again received a two-star "requires improvement" rating.
A sharp reversal since 2022/23
The company's own annual performance reports show how quickly the position changed. Pollution incidents per 10,000km of sewer fell to 16.29 in 2022/23, then rose to 27.93 in 2023/24 and 45.00 in 2024/25. That last figure was about 2.3 times the 2024/25 performance commitment level of 19.50. In 2025/26 the company reported 2 category 2 and 324 category 3 wastewater incidents, about 42.15 per 10,000km.
Spills fall, incidents stay high
Storm overflow numbers moved the other way. In its April 2026 results, United Utilities reported 23% fewer spills and 27% shorter spill duration than the prior year, and it targets a 60% cut in spills by 2030. Fewer spills have not yet brought incident counts down to the levels of 2022/23.
Where the money is going
Investment is concentrated in sensitive catchments. A £200 million Windermere program covers 15 projects, with Ambleside storm tanks due by December 2027. More than £375 million is planned over four years for 20 storm overflows across the Liverpool City region. At Fleetwood, where the company was fined £900,000 in September 2026, it has committed more than £100 million.
Which parts of the wider system carry the greatest risk, how could the 2026 cost change decision alter funding, and what does the planned single regulator mean for oversight? The full report, Water Systems Overview: United Utilities, is available for USD 499. For a free overview, read the United Utilities Utility Snapshot.