A do-not-swim warning at one of Kent’s most popular beaches is “nothing short of devastating”, say furious residents.

The water quality off Deal has been downgraded to “poor” following investigations by the Environment Agency (EA).

The site was rated “sufficient” last year - but increasing levels of bacteria such as E. coli have resulted in the new ranking which will now remain in place for 12 months.

It has led to people being warned against swimming in the sea, something residents fear will put visitors off.

The new score comes seven years after Southern Water announced Deal would see a £3.9m investment to improve water quality in the area.

The water company said this week how it thinks “holiday homes with poor plumbing” could have contributed to the fall in quality.

But the ranking has thrown the town’s annual Boxing Day Dip into doubt as organisers are “urgently seeking clarification” on whether the event can go ahead.

It usually attracts 500 participants and about 2,000 spectators, raising thousands for various charities.

This week, Deal mayor Cllr Oliver Richardson said his concerns go beyond the festive period as “our lives are intertwined with the sea”.

“It is nothing short of devastating… it is what connects us and it forms part of who we are as a community in Deal,” he said.

“Our beaches are enjoyed by all of us and welcome the great number of tourists that support our local economy.

“We also have a long-established fishing trade and many take to the pier to fish throughout the year.

“The full impact on our lives and marine life is yet to be determined.”

Tests by the EA have uncovered heightened traces of E. coli and intestinal enterococci, which is found in human waste and can cause diarrhoea and sickness.

The town’s current score will remain in place until November 2025 when a new classification will be released following tests between May and September.

Dover District Council (DDC) has introduced the do-not-swim warning following guidance from the EA.

It has put up a temporary sign outside the Royal Hotel car park near the town pier, but a more permanent one will shortly be in its place.

Deputy leader Cllr Jamie Pout (Lab) says the results are “not acceptable”.

“We are committed to holding the EA to account and working with key stakeholders to understand how they intend to improve and maintain our water quality,” he said.

“The quality of our beaches and waters within our district are pivotal to our environment, leisure and economy, and we will do all that we can to ensure that those responsible for water quality are actively improving and maintaining it to the highest standards.”

Earlier this year, Southern Water said it had spent the £3.9m funding pot on repairing sewers and refurbishing pumping stations in 2017.

In a statement this week, it said bathing water quality “is very rarely impacted by a single issue”.

“No high samples correspond with combined sewer overflow (CSO) releases,” a spokesman said.

“Instead, we must work with the local authority and other partner organisations to identify all likely sources of pollution including misconnections/illegal connections, private drainage and our own sewers.

“During the summer, the EA advised it had increased testing at Deal Castle, but has yet to link any issue with water quality there back to Southern Water.”

The spokesman added how suspected pollution “can come from a variety of sources”.

“Deal Castle was rated as sufficient in 2023 due to a particularly wet summer where pollutants, including faecal bacteria, will have been washed off farms and roads into the sea,” they added.

“The rating was excellent or good in the previous three years.

“We’ve been working with the council and the EA to investigate potential sources.

“We found a number of illegal connections in the area where waste pipes from homes were wrongly plumbed into surface water only drains.

“One possibility is holiday homes with poor plumbing and this will be a focus of investigations.

“High samples appear to correlate with holiday periods when many holiday homes in the area are in use.”

Residents KentOnline spoke to this week said the new score is “not what the town needs”.

Sophie Woolls, manager of the Sea View fish and chip restaurant in Beach Street, said it is “absolutely a worry”.

“We want people to come down to the seaside to have a swim and come in and get some fish and chips,” she said.

“I think this will put people off and they won’t come down. It’s all over social media.”

Graham Stiles, owner of the Kings Head pub in Beach Street, said the uncertainty over the Boxing Day Dip is a “crying shame”.

“A lot of charities in the town benefit from that event,” he said.

“The announcement shocked me and now there is a lot of concern.”

Pub customer Dave Carter added: “The Boxing Day Dip has been integral to Deal for years. It's an event that has become a tradition.

“To cancel it would be a devastating blow. It would affect a lot of pubs on Boxing Day.

“But all year round a lot of people go swimming every day in Deal.

“And quite honestly the water quality hasn’t been brilliant anyway. I guess, like with a lot of things, you take your chance.”

The Rotary Club of Deal, which organises the dip alongside The Deal Pirates, has suspended its online bookings and publicity of the event.

Club secretary John Utting said: “It is disappointing but we need to do this until we get clarification of the situation from the experts involved, the EA, DDC and Southern Water.

“The most important thing is the safety of our dippers.”

In a statement, an EA spokesman said “specialist officers” from the authority are working with Southern Water and DDC.

“Bathing waters are hugely important for communities and for the environment – and we know there is growing public demand for bathing sites across the country,” he said.

“While overall bathing water quality has improved in recent decades due to targeted investment and robust regulation, the poor results for Deal show there is much work still to do.

“Pollution comes in many forms and may come from multiple sources.

“Yes, Southern Water and the water industry can do more, but water quality can be affected by bad plumbing, oil and fats poured down the sink and into drains, wet weather like the summer we had last year washing pollutants into rivers and seas; run-off from vehicles, animal faeces, farming and even littering.

“We all need to play our part in improving water quality.

“The public can find out where best to swim by getting the latest information on water quality at Deal, the rest of Kent and England at our Swimfo website.

“Any concerns about water quality in our rivers and seas should be reported immediately to our 24-hour incident hotline: 0800 807060.”

Elsewhere in Kent, a do-not-swim warning is now also in place in Dymchurch on Romney Marsh after its water quality fell from “sufficient” to “poor”.

Nearby Littlestone beach has kept its “poor” grading, but St Mary’s Bay has been upgraded to “sufficient”.