Millions of people are missing out on support with their water bills worth hundreds of pounds, experts have warned, as Ofwat approved plans for future increases.

The water regulator is set to give five water suppliers permission to increase charges for customers in the coming years to fund an extra £3.4bn in spending.

Thames Water has provisionally been allowed to increase bills, as well as Severn Trent Water, Southern Water, Wessex Water and South East Water.

It follows Ofwat already allowing water firms to increase bills by 36 per cent between 2025 and 2030.

The move comes as millions of customers are falling behind on their payments, with figures from Money Wellness showing that the average water debt for their customers is now £1,163 and increasing year-on-year.

The advice group has urged struggling households to check if they are eligible for social tariffs which can reduce water bills by an average £190.

Every water company operating in England and Wales must legally provide a social tariff, but eligibility and the amount of savings differs between each.

Sebrina McCullough, director of external relations at Money Wellness, said: “We speak to people who have been struggling with their water bill without realising there may be help available.

“The rules are different depending on which water company you're with, so it's worth checking rather than assuming you won't qualify.

“If you're on a low income or your circumstances have changed, don't just carry on paying the full bill without checking.”

Because water providers can’t be chosen like energy providers, the support is often criticised as a ‘postcode lottery’. Thames Water offers as much as 99 per cent off bills for struggling households, while others cap support at 20 per cent, or even operate on a limited first-come, first-served basis.

Last year, almost two million households received support through a social tariff. While £190 is the average, many households can save as much as 50 per cent of their water bill, which this year would equate to a £319.50 reduction.

All water companies will require their customers to be in financial hardship and struggling to pay their water bills to qualify for a social tariff. This is often based on household income alone, but sometimes takes into account which benefits the bill payer claims.

Certain customers can also have the amount they pay limited by qualifying for the WaterSure scheme. To be eligible for this, households must have a water meter and be a high water user because they either have a specific medical condition or three or more children living at home.

Over a quarter of a million households currently benefit from the scheme, saving an average £325 each. Qualifying for WaterSure on medical grounds also often exempts the household from any hosepipe bans.