‘Disgusting’ UK water companies ‘must be investigated’ for illegally spilling sewage during dry weather

Three major water companies have been slammed as “disgusting” after a BBC investigation found they had discharged sewage illegally last year during dry weather.

According to the investigation, Thames, Wessex and Southern Water all released sewage when it was not raining for 3,500 hours in 2022, a total of 388 times - in breach of their permits.

Water companies are only allowed to release sewage into rivers and seas when sewer networks and pipes become overwhelmed due to factors such as heavy rain.

Releasing sewage during periods of dry weather, known as “dry spilling”, is illegal under environmental law as it can lead to higher amounts of sewage in waterways.

The research by the BBC’s climate and data teams suggests that there were even spills by all three companies on 19 July 2022 when it was the hottest day on record as temperatures peaked to 40C.

Josh Harris, Head of Communications at environmental group Surfers Against Sewage, told NationalWorld that the reputation of water companies is “sinking lower and lower” and they “must immediately be investigated by the authorities.”

He said: “This illegal behaviour directly contravenes water company’s permits and all whilst they siphon off millions of pounds into shareholder dividends and director pay. Water companies have shown time and time again that they are not to be trusted, and it’s time to hit them where it hurts, with tough enforcement.”

Water UK, the industry body, told BBC News that the spills "should be investigated" while the Environment Secretary Therese Coffey said it “seems extraordinary on the hottest day of the year that there may be releases.”

Across the Wessex Water region, from the Dorset coast to the Bristol area, BBC analysis identified 68 sites where sewage may have been discharged illegally last year - with spills starting on dry days appearing to have lasted for more than 1,500 hours.

Wessex Water said the spills were caused by groundwater coming up into pipes and forcing it to spill. It also contested some of the other spills highlighted by the BBC, saying that out of the eight Wessex Water sites identified there were no discharges at five of the sites.

A Wessex Water spokesperson said: “This a known issue caused by high groundwater which, unlike rainfall that stops relatively quickly, continues for days or even months. None of these overflows cause rivers to fail to meet ecological standards.

“We’re using nature-based solutions to treat groundwater affected sites, and by 2025 we will have completed or progressed 28 schemes in our region.”

However, the EA told the BBC that any dry spills due to groundwater are a breach and are illegal.

It was found that Southern Water illegally released sewage at 25 sites across its area last year for a total of nearly 800 hours.

John Penicud, head of wastewater at Southern Water said ‘dry spills’ “are a complex issue” as “water is a powerful force of nature”.

He said: “High groundwater conditions can lead to rising water finding the path of least resistance into a network of sewer pipes. A discharge made up of groundwater is not caused by rainfall and can happen in dry weather. It is required to be reported as a ‘spill’.”

Thames Water dry-spilled for 1,253 hours in 2022 at 49 overflow sites. A frequent spill appeared to occur at Thames Water’s Longbridge Road overflow site in east London which releases sewage into Mayes Brook.

Last year the overflow spilled for nearly 200 hours with BBC research estimating that about a quarter of those hours were from dry spills.

A Thames Water spokesperson told NationalWorld that “there are a number of methodologies for defining and calculating why and how dry day spills occur” and the EA’s methodology “is still being determined”.

The spokesperson added: “We regard all discharges of untreated sewage as unacceptable, and we have planned investment in our sewage treatment works to reduce the need for untreated discharges.”

It is likely that more spills would have occurred last year as Thames Water only monitors 62% of its overflow points, while Wessex monitors 91% and Southern 98%.

An EA spokesperson said the agency is conducting its “largest ever criminal investigation into potential widespread non-compliance by water and sewerage companies at thousands of sewage treatment works” and its “tough enforcement action has already led to over £150m in fines since 2015.”

The spokesperson added: “We will always pursue and prosecute companies that are deliberately obstructive or misleading – and work constructively with those driving improvements. We are also improving how we regulate the sector – including expanding the number of officers focused solely on regulation, increasing compliance checks and recruiting more data specialists able to translate storm overflows monitoring data into stronger regulatory intelligence”.

Water Minister Rebecca Pow said the “volume of sewage discharged into our waters” is “utterly unacceptable” and “it’s why our Plan for Water means more investment, stronger regulation and tougher enforcement, tackling every source of pollution and ensuring swift enforcement action is taken against those who break the rules.”