Water bills could rise by almost £15 a month to stop raw sewage being spilled into rivers, a Thames Water boss has said.

Richard Aylard – Thames Water's sustainability director – said the company planned £18.7 billion in improving its network, which has struggled to contain sewage during heavy rain. But he said that people’s water bills would have to rise to pay for it.

Mr Aylard said the investment included ‘millions of pounds worth’ of work to improve sewage works that have discharged into rivers. He said: “You are talking millions of pounds worth of investment at those sewage works.

“We have got a big programme. We’ve got work planned at more than 250 of our sites but that’s over the next five years. Each of those is a multi-million pound project.”

READ MORE: ‘Kids walked through raw sewage spill for days’ near school

He added: “Yes it does involve an increase and that’s been modelled - £14 a month, it’s something like that.”

Thames Water has come under fire for the amount of times raw sewage is discharged into rivers.

The water company says it discharges sewage into rivers when its systems are unable to cope with the amount of water flowing into it during heavy rain. But it says this should only happen when storm tanks have filled up.

Yet treatment works in the Bracknell and Wokingham areas discharged into The Cut and the Emm Brook repeatedly during the heavy rain this month – and for several hours at a time.

Mr Aylard said investment could pay to stop ‘infiltration’ of rainwater into sewers, as well as to expand treatment works and storm tanks.

But Thames Water is burdened with some £14.7 billion of debt, and has faced questions about why it paid £37 million in dividends to its parent company in the year to March 2022.

READ MORE: Thames Water pumps sewage into The Cut in week of Storm Henk

For its part, the company says it hasn’t been able to invest enough money into its infrastructure as regulator Ofwat hasn’t allowed it to charge customers more.

Now it wants permission to increase the average monthly water bill by £14.55 from 2025 to 2030.

Mr Aylard was speaking to Wokingham Borough Council’s overview and scrutiny management committee on Tuesday, January 16.

Councillor Adrian Mather asked whether Thames Water’s debt meant it could afford the investment. He added: “Does this significant amount of investment depend upon a significant increase in water service bills to our residents?”

Mr Aylard said that it would – but that Ofwat would first need to approve its investment and pricing plans.