Plans afoot for £3.7bn Windermere wastewater tunnel
In a bid to restore and protect water quality at the famous lake, United Utilities has partnered with a coalition of local authorities, regulators, and activist groups to develop a 12-mile pipeline to reroute sewage for treatment and discharge via either the River Level or Ulverston.
Results of a feasibility study conducted by Jacobs and Mott MacDonald have been released, with two clear options proposed to reduce the expected number of algal bloom exceedance days per year from 24 in 2079 to zero.
Billed as a 100-year solution to water quality problems in the lake, the options all focus on a tunnel to divert waste that otherwise would have discharged into Windermere. More than just a diversion and a tunnel, the proposals would include other wastewater interception tactics, new sewerage connections, sustainable drainage measures, and enhanced treatment capability.
This would represent a 75% increase in wastewater infrastructure.
The cost of this project, dubbed Only Rainwater into Windermere, would be an estimated £3.7bn according to the development coalition, which consists of the Environment Agency, Lake District National Park Authority, Save Windermere, Love Windermere, and Westmorland and Furness Council.
Describing the lake as the “jewel of the Lake District National Park,” coalition convener Edward Twiddy explained why a large-scale intervention is needed, rather than just maintenance, to improve the quality of the lake and protect the area’s economy.
“Rather than spending £2.5bn on incremental interventions that may never fully achieve these outcomes, and that would bring decades of disruption to communities and businesses, this report presents a £3.7bn investment capable of delivering £7.5bn of benefits,” he said.
“This is ambitious. It is different. But Windermere is unique, and if we are serious about protecting it for generations to come, we need to be prepared to think bigger and act bolder.”
United Utilities chief executive Louise Beardmore added: “This is about far more than infrastructure. It’s a chance to protect and restore one of the nation’s greatest natural treasures through ambition, innovation and partnership.
“The coalition has set out a clear path forward, and we’re ready to work with government, regulators, delivery partners, and local communities to take the next steps on that journey.”
United Utilities is on the hunt for a design and integration partner for Only Rainwater into Windermere. The contract has an estimated value of £600m, excluding VAT and is expected to last 13 years from 1 April 2027. You can find out more information about the tender by using notice identifier 2026/S 000-099229 on the Government’s Find a Tender portal.
