Giant tunnel proposed to clean up Windermere’s sewage problem

United Utilities, environmental campaigners and local authorities have proposed a £3.6bn scheme to stop sewage entering Windermere, where nutrient-rich discharges are linked to summer algal blooms. The plan matters because the lake is central to the Lake District, a UNESCO World Heritage site, and the government must decide whether the proposal should be developed and how it should be funded.

The scheme would connect 12,800 people to the sewage network, build up to 86 miles of infrastructure and construct a 12-mile tunnel leading to a new treatment works. Two options would discharge treated water into the River Leven or the Irish Sea near Ulverston; estimated costs could add up to £3.17 a month to United Utilities customers’ bills, or up to 35p a month to bills across England if funded nationally. Campaigners called the proposal a milestone but said it must lead to action.