Every water firm in England and Wales under investigation over sewage spills

Ofwat opens cases against Severn Trent and three others, days after they faced criticism over huge bill rises

The water regulator is taking action against four more water companies, including Severn Trent and United Utilities, meaning every wastewater company in England and Wales is under investigation over sewage spills.

Ofwat said it had served formal notices on Dŵr Cymru Welsh Water, Hafren Dyfrdwy, Severn Trent and United Utilities, asking them to provide evidence for its investigation into companies’ wastewater management in England and Wales.

The regulator has looked at the companies’ environmental performance and data about how often they spill from storm overflows. It said this had heightened its “concerns that these companies may not be fulfilling their obligations to protect the environment and minimise pollution”.

Last week, Ofwat was criticised for letting water companies put up bills by an average 21%, or £94, over five years to fund improvements in environmental standards, at a time when customers have endured poor service, sewage dumping and leaks. This was described as a “bitter pill” by the new chancellor, Rachel Reeves.

Campaigners for clean water, including the former Undertones singer Feargal Sharkey, argue that customers are in effect paying twice, and that they should not be paying for infrastructure investment that should have already been carried out to comply with companies’ operational permits.

Severn Trent and United Utilities said they would work “constructively” with Ofwat.