Finest Filters, a firm specialising in water filtration, analysed Instagram posts and hashtags associated with wild swimming to identify the top 20 most popular open water swimming locations in the UK.
Loch Ness came top of both the most popular safe wild swim spots, and the list of the most popular including unsafe areas – with 420,169 posts. The only other Scottish location to feature was the Faerie Pools on the Isle of Skye, which came in third and fourth respectively at 87,387 posts.
Among other top sites to feature were Hampstead Heath, Lake Windermere, and a selection in Snowdonia.
Finest Filters also compared the results using interactive maps developed by The UK Rivers Trust and Surfers Against Sewage, a marine conservation charity to determine if the water is safe for swimming.
It found that a quarter of the 20 most popular sites in the UK aren't safe for such activity, although none of these were in Scotland.
The River Ouse in Yorkshire, the River Derwent in Derbyshire, Port Meadow in Oxford, the Serpentine Lido in Cambridgeshire and Grantchester Meadows in Cambridge were found not to meet water quality standards set out by the EU Water Framework Directive, Finest Filters said.
It added this is largely due to how the UK handles its sewage, and it cited a report published by the WWF outlining how there are more than 18,000 sewer overflows across England and Wales, with roughly 90 per cent of them emptying directly into rivers.
Finest Filters also said that in 2019, The Environment Agency predicted that by 2021, 19 per cent of rivers could pass the basic standard of health – but doubts have been cast on the UK Government’s ability to achieve this target.
It also comes amid a surge in the popularity of open water swimming in lockdown.
The Outdoor Swimming Society’s membership has grown from 300 in 2006 to 125,000 this year. The organisation also offers detailed safety advice, such as doing research on the location before your swim, and assessing the risks every time.
Additionally, campaigners calling for action regarding the quality of water at popular Edinburgh swimming spot Wardie Bay have welcomed Edinburgh’s council backing their bid.
Adam Green, marketing director at Finest Filters, said: “If lockdowns have taught us anything, it’s how important spending time out in nature is for our health and wellbeing.
“But if these results are any indication, we are falling short in ensuring that natural water spots remain clean and healthy, which can have severe consequences on the health of local populations and ecologies.
“Now more than ever, that we take steps to safeguard the health of UK waters for the good of the nation. For anyone looking to jump into UK waters this summer, I highly recommend doing research before heading out. There are some great resources that are available to help you stay safe and up to date with the latest information.”