The majority of popular inland bathing spots in the UK surveyed in a report have been found to be unsafe for swimming.

In a representative sample of popular swimming and water sports locations, 60% were found to have pollution at unsafe levels, the annual report from campaign group Surfers Against Sewage found.

Forty locations were sampled weekly by volunteer citizen scientists throughout the 2023 bathing season. Twenty were popular sites for bathing, and 20 were upstream of a nearby sewage overflow associated with those swimming spots. Using Environment Agency methodology, 24 of the 40 locations would be deemed “poor” quality, and four of 20 bathing sites showed a clear decrease in water quality from locations upstream to downstream of a sewage overflow.

The report highlights that this year, untreated sewage was discharged more than 399,864 times into UK waterways – the equivalent of more than 1,000 discharge events every day. Surfers Against Sewage has also reported 1,924 cases of sickness due to suspected sewage pollution in the last year – nearly triple the number of cases reported in the previous year. The cases resulted in 1,987 days taken off sick.

The case of Reuben Santer, a physics teacher at a secondary school in Exeter, is highlighted in the report. He contracted an incurable condition called Ménierè’s disease after surfing at Saunton Beach in Devon. Santer said his doctors told him the infection was due to a virus or bacteria entering his ear during his surf. He had to stop working for a time after his infection.

Santer said: “I have never been anxious about anything in my life, but this experience has definitely made me worried that symptoms will come back when driving, surfing, at work, or in any situation where vertigo could be dangerous.”

After the Guardian revealed that the UK is to diverge from EU water monitoring standards in England, campaigners fear the situation could worsen further.

Giles Bristow, CEO of Surfers Against Sewage, said: “Yet again, our annual water quality report reveals the complacency and disregard of governments, water companies and regulators towards the health of rivers and coastlines in the UK – and by extension people’s health. How much do our blue spaces need to suffocate in sewage before those we elect to keep us safe and protect our environment wake up and smell the shit?

“We are seeing failure at every level – from governments and regulators failing to enforce the law, to water company fat cats pocketing dirty money and refusing to clean up their act – with the general public ending up the biggest loser every time. How many times can we say ‘enough is enough’? Our leaders need to prioritise transparency, ensure laws and regulations are properly enforced, and prevent water companies profiting from pollution.”

Steve Reed, the shadow environment secretary, said: “The water industry is broken after 13 years of Tory government, with stinking, toxic sewage lapping up on our rivers, lakes, and seas. It is disgusting that families and children cannot enjoy our waters without the threat of getting sick. Despite this gross negligence, consumers are now expected to pay higher water bills, whilst CEOs are pocketing millions in bonuses.”

The water minister, Rebecca Pow, said: “We agree the volume of pollution in our waters is utterly unacceptable, and this is the first government in history to take such comprehensive action to tackle it. Our plan for water is delivering more investment, stronger regulation and tougher enforcement to ensure every overflow is monitored, reduce all sources of pollution and hand out swifter fines and penalties.

“This plan includes targets so strict they are leading to the largest infrastructure programme in water company history – £60bn over 25 years – which in turn will result in hundreds of thousands fewer sewage discharges.”