Loads of you will be planning days out this bank holiday weekend, but there's bad news if you were planning to hit the beach.
Experts say bathing water at Britain's beaches is more polluted than usual because of last year's stormy weather.
They say the floods washed sewage, which is what comes out of our toilets, into rivers and the sea.
So the advice is not to go swimming for 24 hours after storms or heavy downpours.
The Good Beach Guide shows that the number of beaches with excellent water has fallen by 10% since last year.
Of the 779 tested this year, only 443 got a top rating - 52 less than last year.
Gill Bell, from the Marine Conservation Society, said: "We would recommend that you would never go swimming after we've had heavy storms and lots of rain for at least 24 hours, just to make sure that there's no sewage in the water."