Image description: Long-range view over the Lake District. Image by Dave Noonan / Pixabay.

According to a comprehensive analysis of water quality in England’s largest lake, bathing water quality is poor throughout the summer across most of Windermere, indicating high levels of sewage pollution.

the Big Windermere Survey uncovered high levels of bacteria found in human faeces – Escherichia coli (E coli) and intestinal enterococci (IE) – indicating sewage pollution, and were found to be highest in the summer months, when the lake is popular for activities such as swimming and water sports, with many holidaying in the Lake District.

350 citizen scientists took more than 1,000 samples over two and a half years in the Big Windermere Survey to provide this data. Their results include data on water quality from many areas of the lake that have not previously been analysed for water quality.

High levels of phosphorus were also found in sampling, with the north and south areas of the lake meeting standards for moderate rather than good. Under the water framework directive, which governs the monitoring of UK waters, the government is signed up to a target to achieve at least “good” ecological status in all water bodies by 2027 – including for phosphorus concentrations.

Lake Windermere in the Lake District is a UNESCO world heritage site visited by millions of people a year, however last year United Utilities 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.