Water regulator Ofwat has said it has “serious concerns” over the sewage treatment works of five water suppliers.
Anglian Water, Northumbrian Water, Thames Water, Wessex Water and Yorkshire Water submitted reports in December which worried the regulator, it said.
Ofwat interim boss David Black said: “The data that emerged at the end of last year suggested widespread shortcomings in how water companies were running sewage treatment works. The first phase of our investigation suggests those concerns are credible.
“We have identified shortcomings in most water and wastewater companies and are continuing to investigate. But we have already seen enough in five companies to cause serious concern and warrant us taking further action.”
Ofwat said the information it was sent in December raised one of several concerns for each company. Either it reported a large number of wastewater treatment works which might not be meeting their environmental rules, raised concerns about how the company meets environmental obligations, or did not show the company’s workings.
Mr Black said: “We will now dig deeper into what these five companies have been doing, with the prospect of formal enforcement against them if we find they are failing on obligations Ofwat enforces.”
“We will have further questions for all companies on this. In the meantime, we expect them to make quick progress in addressing any potential non-compliance they might have, whilst strengthening how they manage their environmental obligations as a whole.”
BusinessLive contacted the suppliers for comment, with all five saying they would cooperate with Ofwat's investigation.
A spokesperson for Yorkshire Water said: “We take our commitment to care for the environment very seriously. We will of course be cooperating fully with the investigation and it would be inappropriate to comment any further while it is ongoing.”
A Thames Water spokesperson said the firm was already taking action to reduce discharges of untreated sewage and was taking the matter "very seriously."
They added: “We have allocated an unprecedented amount of investment directed towards safeguarding our rivers and streams, including spending £1.25bn on maintaining and improving our operational sites, including contributing to the health of 745km of rivers across London and the Thames Valley."
A Wessex Water spokesperson said: “Wessex Water is undertaking a thorough investigation, as part of an industry-wide programme agreed with the Environment Agency and Ofwat, into the accuracy of flow measurement and any implications for full to flow treatment (FFT) at all of its treatment works with flow consents.
“Findings are shared regularly with the Environment Agency and we are working with Ofwat to provide the further information they have now requested.”
Richard Warneford, wastewater director for Northumbrian Water, said: “We recognise the gravity of the investigation, will fully comply with the requests made and take our responsibilities very seriously. We were already working closely with our regulators on how we monitor sewage treatment works and have active programmes of work that we are investing significantly in at present."
An Anglian Water spokesperson said: "We will, of course, continue to support Ofwat with the information they request. We’ve been transparent throughout and the regulator could have asked us at any point for further detail, which we would have provided.
"We want the public to know they can trust Anglian Water, and that we take our environmental obligations very seriously. We’re already ahead of schedule delivering our £800m programme of environmental improvements between now and 2025, which is specifically targeted at areas where we know we can make a difference."
Earlier this year MPs on the Environmental Audit Committee said that England’s rivers had become a “chemical cocktail” of sewage, agricultural waste, and plastics.
Southern Water was handed a record £90m fine for 6,791 unpermitted sewage discharges last summer. Ofwat said on Wednesday (March 9) that it was keeping an eye on Southern Water’s compliance package.
Only one water company – Hafren Dyfrdwy – did not report any treatment works that potentially did not meet a specific set of rules in the environmental permits.
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