Water companies will be forced to pay out a net total of £70 million to customers after falling short of performance targets, industry regulator Ofwat has confirmed.

The fines for underperforming suppliers will be passed onto customers through lower bills over 2024 and 2025.

Most companies failed to meet key targets on reducing pollution, leakages and supply interruptions, Ofwat found.

Ofwat judges the performance of water companies in England and Wales each year against the “stretching” targets they set in 2019 for a five-year period until 2025.

Thames Water will be ordered to pay out the most to its 15 million customer base, of nearly £74 million.

The struggling firm faced crisis talks earlier this year over its massive £14 billion debt pile, but it managed to secure an emergency funding package from shareholders.

The watchdog last month said Britain’s biggest water supplier has “significant issues to address” over its financial strength.

Anglian Water customers will see more than £27 million taken off their bills and Dwr Cymru about £24 million.

Meanwhile, some companies will be able to charge customers more after improving their performances, according to Ofwat.

Severn Trent Water will be allowed to add £89 million to the bills of the 4.6 million customers it serves from next year and United Utilities can charge more than £25 million.

Ofwat said 12 firms will have to return around £193 million to customers, partially offset by five firms charging about £123 million more, resulting in a net total of £70 million being paid out.

The regulator had said in September that firms would return a net total of £114 million, but that amount was provisional until the review process was completed.