Thames Water set to be sued over reporting of sewage spills

The business, along with five other water companies, could pay over £800 million in compensation to more than 20 million customers if the cases are successful.

These claims come after it was revealed that Thames Water’s total number of pollution incidents increased from 271 in 2021 to 331 in 2022.

Only six of Thames Water’s 17 serious pollution incidents were self-reported to the Environment Agency, which is the worst performance in the sector.

Professor Carolyn Roberts, an environmental and water consultant represented by Leigh Day Solicitors, claims these water companies have broken competition laws by misleading the Environment Agency and Ofwat.

She alleges they have been underreporting the number of sewage discharges, resulting in customers being “unfairly overcharged” for wastewater services.

The first claim, brought on behalf of eight million people against Severn Trent Water, is estimated to be worth more than £330 million.

Further claims will be brought against the other companies in what Leigh Day said is the first environmental collective action case of its kind.

Prof Roberts said: “Like many others across the country, I have viewed with horror the escalating number of stories in the media regarding the volume of sewage discharged into our waterways and on to our beaches.

“The population of the UK has a right to expect that our rivers, lakes and seas will generally be clean, except under exceptional circumstances.

Thames Water have allegedly overcharged customers. (Image: PA)

“It appears that because of the serial and serious underreporting at the heart of these claims, water companies have been avoiding being penalised by Ofwat.

“I believe this has resulted in consumers being unfairly overcharged for sewage services.”

Anyone who paid a water bill to the six companies from April 2020 may be entitled to compensation if the claims are successful.

Leigh Day is seeking money for customers on an opt-out basis, meaning people only have to come forward to claim their compensation if the case is successful.

It is bringing Severn Trent Water to the Competition Appeal Tribunal and will issue five further claims against the other water companies over the coming months.

If successful, solicitors expect any compensation to be paid by the relevant water company and shareholders, not by raising customer bills.

A Thames Water spokesperson said: “TWUL is aware of a claim threatened by Professor Carolyn Roberts.

“TWUL has engaged cooperatively with Professor Roberts to explain that the threatened claim is without merit. No claim has yet been issued against Thames.”