Tough new EU rules could mean that some of England's most popular beaches become no-go zones for swimmers.
A new European directive will be enforced in May 2015, with harsher rules on water safety.
According to the Daily Mail, one in ten of the country's registered swimming beaches will fail the new tests, Environment Agency research has found.
At beaches with water that doesn't meet the new standards, holidaymakers will find signs warning them against swimming.
Beaches that are currently considered safe but are projected to fail next year include Porthluney Cove and Seaton in Cornwall, all three beaches at Blackpool in Lancashire and Combe Martin and Mothecombe in Devon.
The news comes after it was reported the driest summer in a decade had improved sea water quality in a number of UK bathing beaches.
A record number of UK beaches achieved top water quality awards from a marine charity.
The Marine Conservation Society (MCS) said that last year's dry summer - the driest since 2003 - has resulted in more bathing beaches than ever being "recommended" for their excellent water quality in its annual Good Beach Guide.
There were also fewer failures, with just 14 beaches tested last summer failing to reach minimum water quality standards.
In the North East and South East of England, Scotland and Northern Ireland there were no failures at all, meaning all monitored beaches reached minimum bathing water standards.
MCS coastal pollution officer Rachel Wyatt said she hoped the latest figures would be a boost to UK tourism after several previously wet summers led to a drop in bathing water quality caused by pollution running into the sea and overloaded sewers.
Ms Wyatt said: "It's great news that we are able to recommend more beaches than ever for excellent water quality and it shows just how good British beaches can be.
"The main challenge now is maintaining these standards, whatever the weather.
"Most people don't realise what a big impact the weather can have on bathing water quality, but this has really been highlighted in the last few years.
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