Untreated sewage pumped into Windermere after fault (2024)

Millions of litres of raw sewage were illegally pumped into one of England's most famous lakes after a fault, the BBC can reveal.

United Utilities failed to stop the illegal pollution of Windermere, in the Lake District, for 10 hours in February and did not report the incident to the Environment Agency until 13 hours after it started.

An almost identical incident occurred at the same location in 2022.

The firm says it took urgent steps to resolve the incident in February.

A pumping station in Bowness-on-Windermere, in Cumbria, normally sends sewage to Windermere Wastewater Treatment Works.

But United Utilities documents, obtained by the BBC, show how a telecoms fault on the night of 28 February caused the main pumps to stop.

A separate set of emergency pumps then discharged untreated sewage into the middle of Windermere, which is part of a Unesco World Heritage site.

It is England's largest lake and one of the country's most popular natural attractions.

The documents show the pumps started discharging sewage into the lake at 23:34 GMT and continued intermittently until 09:49 GMT the following day.

When the pumping station is fully operational it is permitted to discharge untreated sewage into Windermere if it’s overwhelmed by rainfall or snowmelt. That wasn’t the case in this incident, meaning this release of sewage into the lake was illegal.

Insiders at United Utilities have told the BBC that, in total, the emergency pumps operated for six hours at nearly 500 litres per second - dumping more than 10 million litres of raw sewage into the middle of the lake.

The water firm says it did not measure the volume of untreated sewage pumped into the lake, but it says the BBC’s estimate of the scale of the discharge is unreliable.

The company says the incident “was caused by an unexpected fault in the telecommunications network in the area, which United Utilities was not notified about”.

Windermere has suffered from algal blooms in recent summers, turning the water green and potentially toxic. The algae is caused by a build-up of phosphorus in the lake, partly caused by both treated and untreated sewage.

Evidence from the February pollution incident suggests that United Utilities failed to take quick and appropriate action to limit the amount of untreated pollution that was released.

Insiders at the water company told the BBC the company would have automatically received notification of the fault shortly after it occurred. They say if an out-of-hours team had been promptly sent to the site, most of the pollution could have been prevented.

Instead, an engineer arrived at the pumping station 10 hours later and stopped the pollution shortly after.

The water company must have known that a telecoms fault at the pumping station would almost certainly lead to sewage being dumped into the lake. This had happened in November 2022 in a near identical incident, as reported by BBC Panorama.

United Utilities says it uses a risk-based prioritisation process in the despatch of standby teams. A spokesperson said: “As soon as we discovered this fault was affecting the Glebe Road pumping station, our engineers took urgent steps to resolve the situation.”

Matt Staniek from Save Windermere, which campaigns for an end to sewage pollution, told the BBC that sewage “remains the single biggest threat to England’s largest lake”.

“Time and time again the same thing keeps happening here in Windermere: United Utilities pollutes the lake and the Environment Agency turns a blind eye to it.”

Equipment failures and pollution incidents like this are supposed to be reported immediately to the EA so they can assess the impact and investigate.

Failure to notify the agency as soon as possible is a criminal offence, according to the site’s environmental permit.

But the EA did not receive the call until more than 13 hours after the telecoms fault, and the start of the pollution.

An insider at EA told the BBC it is difficult to investigate pollution when it is reported after the event.

"If these incidents are reported late then it stops us witnessing the pollution and collecting evidence, and then we have to let them off with a slap on the wrist rather than the more serious punishments that they probably deserve."

United Utilities says it was not able to confirm that a spill had taken place until 12:30 GMT and the “incident was reported to the Environment Agency within an hour of the pollution being confirmed”.

The company also says it took water samples from near the site.

They appear to show the release of sewage had limited or no impact on the lake. But they were collected more than four hours after the pollution had stopped, and were taken on the lake shore, not from the middle of the lake where the sewage was discharged.

Following last year's BBC Panorama investigation, the Environment Agency said it was strengthening regulation, increasing compliance checks and had a new approach to "uncover non-compliance and drive better performance from the water industry".

But leaked documents suggest the EA failed to investigate this incident thoroughly or challenge the water company’s account of events.

The agency’s attending officer also tested the water on the lake shore, rather than from where the sewage had been discharged, and he reported “no visual impact found”.

The Environment Agency investigation did not work out the total duration or volume of the sewage pumped into Windermere.

It subsequently categorised the pollution as a "minor" incident and the only enforcement action taken was a routine “site warning” issued three weeks later.

The investigation appeared to be closed, because enforcement action of this kind is usually the end of the process.

However, after the BBC questioned the Environment Agency about the incident, a spokesperson said: “We are undertaking a thorough investigation into the incident which involves examining further evidence from United Utilities.

"If any water company is found to be in breach of an environmental permit the Environment Agency will take the appropriate enforcement action up to and including a criminal prosecution.”

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