The record rainfall we've had this summer could be bad news for our beaches.
New scientific tests show the number judged to be too dirty to swim in could more than double this year.
In 2011, 10 beaches in England and Wales failed to meet the standard needed for swimming but experts say that could rise to 26 this year.
They say months of heavy rain has swept fertilisers and pesticides from farms into rivers and then our seas.
There's also a problem with sewage pipes overflowing.
Watch Leah's reports to find out more.