Water firms in Kent are among a slew ordered to refund £114m to customers through slashed bills after missing targets.

Thames Water is the company which must return the most, over £101 million, followed by Southern Water which must pay out £43 million.

It comes as the latest blow for the two utility giants which have recently been accused of “dry spilling”, a banned practice of pumping effluent into rivers and seas during dry spells.

Ofwat’s annual report judged firms on pollution incidents, customer service and leakage, with no company being ranked in the ‘leading’ category.

However, 10 firms featured in the ‘average’ category, while seven are ‘lagging’ including Southern Water, Thames Water and South East Water.

The watchdog’s chief executive David Black said while reductions "may be welcome to bill payers, it is very disappointing news for all who want to see the sector do better".

The regulator judges water companies in England and Wales against "stretching" targets set in 2019 for a five-year period.

And if they fail to meet targets, Ofwat restricts the cash they can take from customers and order rebates through cut bills rather than lump sum refunds.

Ofwat also says it is investigating all 11 water and wastewater companies. There are live enforcement cases for six of them for potential failures on sewage discharges into the environment, the watchdog says.

The firms ordered to cut bills are:

• Affinity Water
• Anglian Water
• Dŵr Cymru
• Hafren Dyfrdwy
• Northumbrian Water
• SES Water
• South East Water
• South West Water
• South West Water (Bristol)
• Southern Water
• Thames Water
• Yorkshire Water

While some companies will have to return funds to customers, others will be able to increase bills. Thames Water must return £101m and Southern Water paying £43m.

It is impossible to say how much each household will receive at the moment, with refund amounts depending on a customer’s location and inflation.

Thames Water serves 15 million people with water and wastewater, many of who live in Kent, while Southern Water serves around 4.6 million, it is understood.

By contrast, Severn Trent is able to increase bills by £88m and United Utilities, which serves the north-west of England, by £25m after hitting targets.

A Southern Water spokesperson told KentOnline it is working to “reduce pollutions and leakage and improving customer service” which will “take time to feed through into future performance metrics.”

South East Water’s regulation and strategy director, Oliver Martin called Ofwat’s target “very stringent” amid a year which saw “exceptional challenges” for the industry.

“Customers will receive a reduction in charges in 2024/25 for any penalties we have incurred, and this equates to £5.2m across our customer base,” he added.

A Thames Water spokesman said the firm has seen “a reduction in sewage discharges, internal sewer flooding, and sewer blockages.”

“We’re determined to do better for our customers and the environment.”

Affinity Water did not respond to a request for comment.