According to a new study, the average public swimming pool contains up to 20 GALLONS OF URINE.
A group of researchers in Canada figured it out by testing 23 public pools for traces of an artificial sweetener that's used in a lot of processed foods. Your body doesn't break it down. So when you pee, it's still in there.
One pool they tested was about a third the size of an Olympic swimming pool, and they calculated it had just under 20 gallons of urine. Another one was about half as big, so more like a hotel swimming pool. And it had around eight gallons of pee.
If you crunch the numbers, that means the average backyard swimming pool would have about TWO gallons of urine. We might not pee in our own pools quite so freely though.
They also took samples from eight hot tubs, and they're even WORSE. There was less urine, but also a lot less water to dilute it. One hotel hot tub they tested had THREE TIMES the concentration of urine as the worst swimming pool