Three major water utility companies in the United Kingdom face 168 million pounds ($214 million) in fines for numerous illegal sewage releases into rivers and coastal waters.

The penalties follow the national water industry regulator's most extensive investigation to date into violations that included the discovery of a "catalogue of failure" and "excessive spills".

The regulator, Ofwat, proposed fines of 104 million pounds for Thames Water, 47 million pounds for Yorkshire Water, and 17 million pounds for Northumbrian Water for their mismanagement of wastewater treatment and sewer systems.

Ofwat stated that the water companies "failed to ensure that discharges of untreated wastewater from storm overflows occur only in exceptional circumstances, which has resulted in harm to the environment and their customers".

The regulator also noted a "strong correlation" between high spill levels and operational problems at wastewater treatment facilities, suggesting that these companies have not "properly operated and maintained their wastewater treatment works".

David Black, Ofwat's chief executive, emphasized that investors, not customers, would bear the cost of the fines.

"Ofwat has uncovered a catalogue of failure by Thames Water, Yorkshire Water, and Northumbrian Water in how they ran their sewage works and this resulted in excessive spills from storm overflows," he said. "Our investigation has shown how they routinely released sewage into our rivers and seas, rather than ensuring that this only happens in exceptional circumstances as the law intends."

The announcement came after a BBC investigation earlier this year uncovered that England's water companies may have illegally released sewage 6,000 times in 2022, violating their permits.

The release of raw sewage can cause serious environmental damage and pose health risks to people swimming in affected rivers or seas. The UK's Environment Agency is conducting its own investigation into the environmental impacts of the water companies' discharges.

Seven more water companies will face similar Ofwat investigations and potential rulings later this year, Black said, while suggesting that companies could potentially reduce proposed fines by committing to address the identified problems.

Black said: "This is a draft decision, companies can propose a settlement offer to us, which if they address the issues in terms of fixing the problems and ensuring that this doesn't happen again, then we could take that into account in terms of our final decision.

"These are very serious findings — what we've uncovered is a catalogue of failures, and it's very clear that companies have not been adequately addressing these issues — that reflects the public concern and outrage, and that's why we've acted today."

Environment Secretary Steve Reed agreed the fines were appropriate, saying: "The unacceptable destruction of our waterways should never have been allowed — and it is right that those responsible for illegally polluting our rivers, lakes and seas face the consequences."