Four water companies are under investigation by regulator Ofwat as part of its wider inquiry into sewage spills into rivers and other waterways.
The addition of the four companies to the probe, including Severn Trent and United Utilities, means that Ofwat now has enforcement activities open against all 11 water and wastewater firms in the UK and Wales, it said.
It issued formal notices on Dŵr Cymru Welsh Water, Hafren Dyfrdwy, Severn Trent and United Utilities to gather evidence for the investigation. The move comes after the regulator investigated the environmental performance and data on how the companies spill from storm overflows.
The regulator said the information reinforced its concerns that the companies may not be fulfilling their obligations to protect the environment and minimise pollution.
Enforcement cases against Anglian Water, Northumbrian Water, South West Water, Thames Water, Wessex Water, and Yorkshire Water were launched in 2022 and are continuing. Southern Water is undergoing enforcement monitoring following an even earlier enforcement case in 2019.
David Black, Ofwat’s chief executive, insisted it “demonstrates how concerned we are about the sector’s environmental performance”.
He described it as the “the largest and most complex investigation” Ofwat has undertaken. It would conclude all the cases as quickly as possible so the water companies can focus on delivering the £88bn expenditure Ofwat is hoping its price review plans will unlock to deliver cleaner rivers and seas.
The regulator stressed that opening an enforcement case does not automatically imply the company has breached their legal obligations. Once Ofwat has fully investigated, it will publish details of its findings and, where appropriate, any proposed action to remedy any identified breaches.
Water companies have also been asked by the information watchdog to release more data on the sewage they discharge into waterways.
John Edwards, the information commissioner, wrote to the utility firms in England, Wales and Northern Ireland asking them to publish data on the number and duration of sewage outflows every month, instead of waiting for members of the public to request information.
The information is usually requested through environmental information regulations. It would be quicker and easier for the statistics just to be released, the Information Commissioner’s Office (ICO) said.
Fresh concerns over high pay and bonuses for water company executives have emerged after it was revealed Southern Water awarded Lawrence Gosden, its chief executive, a £183,000 bonus for the year to March 31, increasing his total pay for the year to £764,000.
The bonus came after Southern, which provides water services to more than 4.7 million customers across Sussex, Kent, Hampshire and the Isle of Wight, pitched the biggest increase in customer bills of all English water providers.