Plans have been unveiled for a £3.6bn tunnel stretching 12 miles at Windermere, England's largest lake, which attracts about 18 million visitors a year. The tunnel is designed to prevent sewage from being discharged into the lake, which holds Unesco World Heritage site status in the Lake District.
The proposal, backed by local water company United Utilities and clean water campaigners, would carry sewage away from the lake. The BBC reports that the decision now rests with the government on whether the scheme can progress and whether the £3.6bn price tag represents value for money.
Why the tunnel is needed
Currently, raw sewage and treated effluent are released into Windermere, with campaigners claiming this causes sections of the lake to turn green each summer through algal blooming, reports the Express.
Louise Beardmore, chief executive of United Utilities, told the BBC the proposals represented a "100-year solution for this lake". She said: "In the UK we invest in five-year periods and so we come along all the time and we do a bit, then we go away and we come back and do a bit more. This is saying we need to do something differently."
She explained that a wide-ranging coalition comprising her company, regulators, local authorities and environmental campaigners had joined forces to draw up the tunnel proposal, known as "Only Rainwater into Windermere", which would see 12,800 residents connected to the sewage network for the first time, alongside up to 86 miles of new sewage infrastructure.
How the cost could be met
One potential way of meeting the considerable cost would be to pass it on to United Utilities' customers, adding up to £3.17 to their monthly bills. Alternatively, the expense could be spread across the whole of England, adding 35p per month to people's bills.
Nigel Wilkinson, from the Love Windermere group, argued the latter would be the preferable option, stating "we believe Windermere is of such national significance and international significance that it is justifiable to treat this as a national asset and fund it accordingly".
Why sewage is discharged into UK waterways
Sewage flowing into our waterways remains a widespread problem across the UK, affecting lakes, rivers and coastal waters alike. Beachgoers regularly face warnings over water quality, while campaigners along the River Wye on the Wales-England border recently revealed that the river had been subjected to thousands of hours of sewage discharge in 2025.
During periods of intense rainfall, the quantity of water surpasses the capability of the sewerage system and treatment facilities. Storm overflows function as pressure release valves to discharge surplus water into nearby waterways, stopping sewage from flooding back into properties and roads.
Insufficient investment and a lack of capacity upgrades to accommodate a growing population have left infrastructure inadequately prepared, and climate change threatens to exacerbate the situation further. United Utilities said: "Rising temperatures will increase these pressures while more intense rainfall places more stress on wastewater infrastructure."
