United Utilities (UU) is set to confirm a reduction in the number and duration of storm overflow operations across the North West last year, when official figures are released by the Environment Agency (EA) later this month.  In the Windermere catchment, the company’s annual event duration monitoring (EDM) submission to the EA records a 28% reduction in spill duration, or 2,460 fewer hours of spills. However, last year the company was accused of failing to report more than 100 million litres of untreated sewage that it illegally dumped into Windermere over a three-year period.

Photo by Tom Fisk / Pexels

New data obtained by Save Windermere under Environmental Information Regulations, and analysed by Professor Peter Hammond from Windrush Against Sewage Pollution, has revealed the full extent of United Utilities’ sewage releases around lake Windermere. The newly disclosed data follows a ruling from the Information Commissioner’s Office (ICO), with UU making information more accessible through a ‘commitment to being more transparent’. The analysis was carried out weeks before water companies are due to submit their annual returns to the Environment Agency, and Save Windermere pre-emptively requested this data before United Utilities submitted its official figures.

The group revealed in 2024 alone, six sewage overflow sites around Windermere released untreated sewage for 6,327 hours, the equivalent of sewage pouring non-stop for 263 days. Since 2020, those same six sites have discharged untreated sewage for 33,410 hours, the equivalent of 1,392 full days. The group vocalised their concern that as Windermere sits at the lowest point in the catchment, all that pollution eventually ends up in the lake, accumulating year after year.