Residents across Buckinghamshire will see money taken off their water bills after the region's water company was fined more than £50 million.

Eleven water suppliers have been hit by fines totalling almost £150 million after they missed targets such as water supply interruptions, pollution incident and internal sewer flooding.

Thames Water, which supplies water to High Wycombe and Aylesbury, performed the worst and will have to returned £51 million to customers in the form of discounted bills, regulator Ofwat said.

Elsewhere, other companies which exceeded their targets will be able to recover more money from customers, meaning they could see their bills go up.

Severn Trent Water, which supplies millions of people with water across England, performed particularly well in the regulator’s review and will be able to increase customer payments by £63 million in the year ahead.

However, Ofwat noted that all the water companies will be permitted to increase charges in line with inflation, using the consumer prices index including owner occupiers’ housing costs (CPIH) – which hit 8.6% in the 12 months to August.

This means that some reductions could be offset by inflation-linked price rises in customers’ bills.

David Black, the chief executive of Ofwat for England and Wales, said: “When it comes to delivering for their customers, too many water companies are falling short, and we are requiring them to return around £150 million to their customers.

“We expect companies to improve their performance every year; where they fail to do so, we will hold them to account.

“The poorest performers, Southern Water and Thames Water, will have to return almost £80 million to their customers.

“All water companies need to earn back the trust of customers and the public and we will continue to challenge the sector to improve.”

Ofwat’s review comes amid greater scrutiny of water companies during a period of drought and with some areas of the country facing hosepipe bans during the summer heatwaves.

Mr Black said in August that targets for areas such as leaks are “challenging but achievable”, revealing that he did have concerns about the performance of some companies.

The yearly targets were set at the regulator’s last price review in 2019 and will be in place up until the next review in 2025.

Customers should see their bills reduced in 2023 to 2024.