Record number of illegal sewage spills in Windermere last year

Sewage spilled illegally into England’s largest lake on a record number of days last year, an analysis of water company data by campaigners suggests.

The analysis, which the BBC had exclusive access to, used United Utilities operational data to establish when the company was discharging sewage into Windermere when it should by law have been treating some of it.

The campaigners from Windrush Against Sewage Pollution (WASP) and Save Windermere identified 140 illegal spill days in 2024, more than in any of the three previous years.

United Utilities told BBC News that the campaigners’ findings were “inaccurate” and some of the data “erroneous”.

The company declined to put in writing, despite repeated requests, any specific examples of mistakes or omissions.

Regulators Ofwat and the Environment Agency are both currently investigating United Utilities operations.

The regulators Ofwat and the Environment Agency have since 2021 been investigating whether the water companies have been treating enough sewage before they start to spill. The EA call it a “major criminal investigation” while Ofwat call it “the largest and most complex Ofwat has ever undertaken”.

Last week Yorkshire Water agreed to a £40m “enforcement action” after Ofwat uncovered “serious failures” in how it operated its treatment plant and network.

Ofwat declined to comment on the campaigner’s findings as their investigation into United Utilities is ongoing.

In response to concerns about United Utilities the Environment Agency last year reviewed all of its environmental permits in the Windermere catchment and says this led directly to the water company tripling its investment plans for the area to £200m.

“We are currently carrying out investigations into suspected pollution incidents on the Windermere catchment and are unable to comment on these in detail until they have reached a conclusion,” an EA spokesperson said when the campaigners’ analysis was shared with them.

“Where we find breaches of environmental permits, we will take the appropriate enforcement action up to and including a criminal prosecution.”