The number of complaints made by households about water companies to the industry watchdog has risen by a record 84% in a year, driven by customer concern and confusion over rising bills.

The Consumer Council for Water (CCW) said the year-on-year increase was the highest in its 20-year history and showed "just how dissatisfied" many people were.

Water customers in England and Wales have been hit with steep price hikes in recent years. The regulator Ofwat has also allowed firms to put up bills by 36% between 2025 and 2030.

Water UK, which represents firms, said it understood that higher bills was never welcome, but the money was needed "to fund vital upgrades".

The total number of complaints to the watchdog rose to 15,115 in 2025-26, from 8,235 in the previous year.

Meanwhile, complaints made by households directly to water companies, which is required before complaining to the CCW, rose by 56% to 321,347.

The top three subjects of complaints to the CCW were measured billing, affordability and billing admin.

Mike Keil, the chief executive of the CCW, said the figures "reflect just how dissatisfied many people still are with the state of the water sector".

He said customers are "impatient to see the benefits" of higher bills.

"Companies need to be clear and open with their customers about how they are investing people's money to deliver real improvements."

The CCW assessed each water company's performance on the number of complaints it received for every 10,000 households it serves, and the amount of effort customers have to put in to get their complaint resolved.

Thames Water and South West Water rated "poor" for both performance measures.

David Bird, retail director at Thames, apologised to customers who "have not received the service they should expect".

"We know bill clarity has been a particular source of frustration, which is why we have launched a programme to redesign them, so they are easier to understand," he said.

Bills for the average Thames customer rose by 31% in 2024, but were a lot smaller this year at 3.4%.

South West Water said: "We know there is more to do to improve our customers' experience. We are taking action by reducing repeat contacts, resolving issues when people contact us for the first time, and ensuring they receive clear, timely communication."

Portsmouth Water and Bristol Water were the only companies to score "good" in both metrics, retaining their position at the top of the rankings as the sector's best performers.

Last month, Ofwat approved bill increases for 13 companies to meet increased pressures on infrastructure and the environment.

Five of those companies — Thames, Severn Trent Water, Southern Water, Wessex Water and South East Water — were already permitted to hike bills in 2024.

A spokesperson for industry body Water UK said: "We understand increasing bills is never welcome, but the money is needed to fund vital upgrades to secure our water supplies, support economic growth and end sewage entering our rivers and seas.

The spokesperson said that 94% of complaints are "being dealt with at the earliest possible stage without the need for further involvement from the consumer body".

"The industry remains committed to improving communication with customers and showing clearly how their money is being used to deliver the improvements they expect," the spokesperson added.