Researchers have finally put a number to the ratio of wee to water in swimming pool and it's not pretty,.
Testing the water in 31 pools in homes, sports centres, and hotels, a Canadian study has found that the average swimming pool contains round 60 litres of urine.
This works out to be roughly 70ml of wee per person and apart from being gross, it could also be harmful.
While wee itself is sterile, the chemicals used to keep pools clean can react with wee and trigger eye irritation as well as respiratory problems that can make asthma worse.
And if you're thinking it's just kids who wee in pools, the study leader Lindsay Blackstock reveals that:
'Although considered a taboo, 19 per cent of adults have admitted to having urinated in a swimming pool at least once.'
Even Olympic swimmers admit to peeing in the pool.
Michael Phelps, the American swimmer who has won 28 medals famously said:
'I think everybody pees in the pool. It’s kind of a normal thing to do for swimmers.