Bathing water quality at some top beaches can drop sharply in winter, internal Environment Agency study finds

Bathing water quality at some of England’s highest-rated beaches can decline sharply during the autumn and winter months when official swimming spots are usually unmonitored, according to an internal Environment Agency (EA) study completed earlier this year.  

The findings of the study – which have not been published, but have been seen by Unearthed – will cause concern among the UK’s many fans of cold-water swimming.  

Swimming outdoors in low temperatures has surged in popularity in recent years because of its reported health benefits. In response to this trend, the EA ran a trial last winter at six well-known beaches across the West Country – all currently rated ‘good’ or ‘excellent’ – to test the feasibility of sampling bathing waters over the colder months. 

Under the current regime, the EA only monitors bacteria levels at designated bathing waters between mid-May and the end of September. This year’s monitoring season ended on Monday (30 September). Based on these summertime tests, each swimming spot is given a rating of ‘excellent’, ‘good’, ‘sufficient’ or ‘poor’. 

However, the EA study found that between October and March there were much-higher levels of E coli and Intestinal Enterococci at half of the beaches in the trial. These are bacteria found in human and animal faeces that can cause gastrointestinal illness. 

The levels found suggested these beaches had bathing water quality last winter that was at least two ratings lower than their official classification.

Academics and campaigners told Unearthed the study demonstrated the need for the UK to move to all-year monitoring of bathing water quality. 

“We demand a water quality testing regime which is based on the reality of how the polluting water industry operates and how people actually use our rivers, lakes and seas,” said Giles Bristow, chief executive of the campaign group Surfers Against Sewage. “In short, it’s 2024, not 1924.

“To the government we say, better late than never but you’re very, very late. It’s time to lift the lid and uncover the quality of our wild waters, year-round.”

Joyce Harper, a professor of reproductive science at University College London and lead author of a recent study on the popularity of cold water swimming among women, said the EA findings highlighted the importance of moving to all-year-round monitoring of bathing water quality.

“If anything, it’s more important to monitor it in winter,” she told Unearthed, because of the “increase in rainfall, which washes pollution into rivers and then ultimately the sea”. 

To the government we say: better late than never but you’re very, very late

– Giles Bristow, chief executive of the campaign group Surfers Against Sewage

“We are polluting our environment which is totally unacceptable,” she added.  “It’s important for our environment, not just the safety of swimmers.”

Unearthed understands that ministers are currently considering options for reform of  the bathing water system. A spokesperson for the Department for Environment, Food and Rural Affairs said: “We recognise there have been changes in how people use bathing waters since the regulations were introduced over ten years ago, and will continue to keep our regulations under review.”

An EA spokesperson told Unearthed that the report “showed that all locations except one maintained a water quality standard of ‘sufficient’ or higher over the winter”. 

“We will continue to work closely with the agriculture sector, water companies and local communities to ensure the highest standard of bathing waters for the public,” they added.

‘Unacceptable’

The EA study reported that at two beaches – Summerleaze in Bude, Cornwall, and Firestone Bay in Plymouth, Devon – the water quality dropped from ‘excellent’ to ‘sufficient’ during the winter months. 

At a third, Exmouth, in South Devon, it fell from ‘excellent’ to ‘poor’ – the worst rating available for a designated bathing water site, and below the minimum acceptable standard. 

By contrast, at two other beaches in the study – Woolacombe, in North Devon, and Fistral North, in Newquay, Cornwall –  the water quality remained excellent throughout the winter months. At Lyme Regis, in Dorset, it improved from ‘good’ to ‘excellent’.

Exmouth, which saw the sharpest decline, is a popular beach for swimming and watersports. Andy Tyerman, from End Sewage Convoys and Pollution in Exmouth (ESCAPE), which represents water users and beach goers in the area, said his campaign group was “disappointed and concerned” by the results for “pilot sites like Firestone Bay and Exmouth”. 

“This study shows an urgent need to understand the broader picture, as this is a single year and a very small sample group across the South West,” he continued. “It is unacceptable that our waters are still routinely used to dump large amounts of untreated sewage.”

The area’s water company, South West Water, has made a commitment in its 2022-2025 plan to  “maintain our excellent bathing water quality standards, all year round”.

“It is clear we are a long way from having excellent water quality all year round,” Tyerman told Unearthed, “and people are right to ask where the money – the highest wastewater bills in the country – has gone?”

Richard Price, Managing Director of Waste Water Services at South West Water said: “Bathing water quality in our region remains a priority, and we fully support efforts to better understand conditions across the 157 bathing waters we serve.”

The company is currently taking daily samples of bacteria levels at 14 bathing waters in an effort to gain a better understanding of how these catchments behave, Unearthed understands.

However, Price said the EA report highlighted both the practical challenges of winter sampling –40% of samples went uncollected because the conditions were too rough – and the relatively “low use” of bathing waters during these months. 

“Beaches like Exmouth, Summerleaze, and Firestone Bay, which are at the bottom of large river catchments, can be affected by a mix of contaminants, including agricultural runoff and animal waste, as well as some human-related sources,” he added.

“The report shows that agricultural pollution is a significant contributor, responsible for about 50% of microbial sources in these areas.”

‘Multiple serious pollution events’ 

The study’s findings indicated that the rise in bacteria levels recorded at some beaches could be linked to wetter weather during the winter months. Heavy rainfall can cause increased runoff of animal manure spread on farmland; it can also trigger sewage releases from overflow pipes, which are used by water companies to reduce pressure on the sewer system during bad weather.

The authors reported a “moderate” correlation between bacteria levels and the amount of prior rainfall at both Firestone Bay and Exmouth over the winter. They also reported that there were “multiple serious pollution events” over the period that may have affected the water quality at Exmouth, which saw the steepest increase in bacteria levels. 

“High bacteria results in the bathing water over winter seemed to coincide with rainfall and pollution events from water company assets,” the report said of Exmouth. 

However, it added that although “these sewage pollution events seem to have contributed to the high bacteria in the bathing water” the samples analysed “suggest that other factors including cattle slurry were also contributing to the high results”.

The report noted that bathing waters’ official classifications are usually based on around four years worth of samples. Each year, a designated swimming spot is sampled up to 20 times between May and September, meaning that classifications are based on around 80 samples over four years. By contrast, the number of samples collected at each beach during the EA’s study last winter ranged from 16 at Bude to 26 at Exmouth. 

The report noted, therefore, that the indicative ratings it gave the water quality at these beaches last winter could not be considered “representative” classifications.

However, in the case of Firestone Bay, the winter rating was actually based on more samples than its official classification. The Plymouth beach was only designated as an official swimming spot in April 2023 and it received an ‘excellent’ rating during its first season, based on 20 samples taken from mid-May to late-September. 

During the winter sampling trial, when 25 samples were taken, Firestone Bay was given an indicative classification of ‘sufficient’, dropping down by two ratings. 

Besides investigating how water quality differed in winter, the EA trial was also intended to analyse how easy it would be to carry out a testing regime in winter, when seas are rougher and more dangerous. It found that overall it was possible to collect 60% of the planned samples, with the rest uncollected due to unsafe conditions. However, there was wide variation, with much lower collection rates on the north coast beaches, which are more exposed. 

The authors concluded that if the project was extended for a further three years it would be possible to “produce a winter dataset comparable with the statutory summer classification dataset” but it would need a 40% increase in resources. 

Unearthed understands that the EA has no plans to extend its winter bathing water project beyond the six initial locations, as they were chosen to be representative of the range of bathing waters across the UK.