Huge tunnel proposed to tackle sewage blighting Lake Windermere
A £3.6 billion proposal has been unveiled to construct a 12-mile tunnel to divert sewage away from Lake Windermere in the UK. Backed by water company United Utilities and environmental campaigners, the project aims to tackle the chronic issue of algal blooming caused by sewage discharges.
Why it matters
Lake Windermere is England's largest lake and a UNESCO World Heritage site, making its ecological health and the long-term infrastructure solution a matter of significant national and environmental interest.
Image source, Getty Images Image caption, Windermere sits at the heart of the iconic Lake District
Environment correspondent Published 21 October 2026, 05:44 BST A £3.6bn proposal to stop sewage being discharged into Windermere, England's largest lake, has been unveiled.
The plans, which are backed by the local water company United Utilities and clean water campaigners, would see a tunnel up to 12 miles (19km) long built to transport sewage away from the lake.
At the moment both raw sewage and treated effluent are discharged into Windermere and campaigners say that is why parts of the lake have been turning green each summer, so-called algal blooming.
It is now up to the government to decide if the plan can be further developed, and if the £3.6bn price-tag is acceptable.
The Lake District is a Unesco World Heritage site and attracts close to 18m visitors each year.
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