Households in England and Wales will pay £10 more on average on their monthly water bills from April, final figures show.

The rise will see the average annual bill hit £603, but there are significant variations between regions.

Water companies have committed extra money for investment in infrastructure, such as reservoirs and more help for struggling customers.

However, consumer groups are warning the rise means more households will fall into debt.

The increase means the average annual bill will rise by £123 – around £10 a month – but millions of households face even steeper rises.

Southern Water customers will see a 47% increase to £703 a year while Hafren Dyfrdwy and South West Water bills are rising by 32%.

Thames Water customers have been warned they face a 31% hike and Yorkshire Water is raising bills by 29%.

Bills for Bournemouth Water customers will grow by 32%.

Other factors, such as whether a customer is metered and how much water they use, means the bill changes will vary considerably for customers depending on their circumstances.

Earlier this week, it was announced that water bills in Scotland will increase by almost 10% from April.

Bill rises for the next five years in England and Wales are being front-loaded, with a big increase this April so that spending on new infrastructure, such as new reservoirs, can get going.

Water UK chief executive David Henderson said: “We understand increasing bills is never welcome and, while we urgently need investment in our water and sewage infrastructure, we know that for many this increase will be difficult.”

He added: “We accept we have not been investing enough [in infrastructure], but we don’t determine how much we invest – that is set by the regulator every five years.”

Water companies say they will also set aside more than £4bn to fund social tariffs – discounted bills for vulnerable people – over the next five years.

But the Consumer Council for Water (CCW), which represents bill payers, said support did not go far enough, as about 2.5 million households were already in debt to their water company.

“These rises will heap considerable pressure on millions of customers who are already having to make difficult choices,” said CCW chief executive Mike Keil.

“Customers want to see investment in improving services and cleaning up our rivers but that can’t come at an unbearable cost to struggling households.”

The CCW said this was the largest rise in water bills since the privatisation of the water industry 36 years ago.

David Black, chief executive of Ofwat, said: “We have pushed companies to double the amount of support over the next five-year period and strongly encourage customers who are struggling to pay their water bills to contact their water company to access this.

“While bills are rising, the £104bn investment we have approved over the next five years will accelerate the delivery of cleaner rivers and seas and help to secure long-term drinking water supplies for customers.”