This revelation comes in a year when campaigners reported that the lake experienced its worst summer of harmful algal blooms.
The analysis was conducted by Prof. Peter Hammond, known for his earlier research that highlighted the extent of illegal raw sewage discharges from English water companies. Hammond examined detailed data on spills and treatment provided by United Utilities, which was made available by the Environment Agency.
Hammond’s findings indicated that permit conditions were potentially breached on up to 70 days during the year at three United Utilities treatment facilities and one pumping station that discharge into Windermere. Breaching permit conditions is considered illegal, and the Environment Agency is currently involved in a criminal investigation into potential illegal discharges from over 2,000 water company treatment plants across England.
During the summer of 2022, a significant portion of the north shore of Windermere, which is England’s largest natural lake and a UNESCO World Heritage Site, was covered with blue-green algae, leading campaigners to describe it as the lake’s worst occurrence of algal blooms. The Environment Agency warns that blue-green algae can produce toxins harmful to wildlife, livestock, pets, and humans.