Discharge of raw sewage into rivers is unacceptable, a top Thames Water official has said – but hinted that increasing charges could be needed to stop it.

Wokingham Borough councillors questioned Richard Aygard, External Affairs and Sustainability Director for Thames Water, on sewage overflows at a meeting on Monday, June 12.

It came after Thames Water discharged sewage water into waterways more than 8,000 times in 2022, 777 of which were storm overflows, according to data published by the Environment Agency in April.

Mr Aygard claimed the discharges occur when heavy rain means sewage treatment plants can’t handle the volume of water they have to process.

He said: “The problem comes if the works is full, the storm tanks are full, and the sewage is still arriving at the works.

“The sewage companies have pumping stations, one in each village. You turn the pumping stations off, you flood the villages with sewage.

“If you’re going to keep them going, you’re going to put untreated sewage into the river. And if you try to block the process somewhere the tanks are going to overflow anyway.

“At that point, you’re allowed to discharge into the river. That’s the bit that we regard as unacceptable. It’s the way the system is designed. But it’s not acceptable.”

He said that Thames Water wanted to get the total duration of sewage discharges down by half by 2030. But he said that required a combination of finding ways to stop rain water getting into sewage pipes, and increasing the capacity of sewage treatment plants.

READ MORE: Thames Water permitted over 8,000 sewage releases into waterways

Councillor Catherine Glover asked whether Thames Water would “use its own resources over the next ten years rather than increasing charges to the consumer to stop discharges”.

But Mr Aygard said that Thames Water needed to deliver returns to its shareholders, or else it would lose their investment. “If they’re not going to get a return on water, you can bet they’re going to invest in telecoms, or energy or railways.

“In terms of major investments, no company is going to be investing unless it’s going to make some kind of return.

“We’re just coming to the end of a ten year period in which the regulator announced it was a decade of declining bills. So guess what’s happened to bills – they’ve come down. I believe and lots of people believe they’ve come down too far.

He said Thames Water would talk to the government, the regulator Ofwat, which sets charges, and customers on charges over the next five years.