Pools are disgusting, Oh, but what about that strong, chlorine pool smell? That eye-watering chemical odor must mean they’re clean, right. Well, sorry, but that’s not chlorine you’re smelling my friend, that’s the smell of trichloramine, a gas created when chlorine reacts with the chemicals in your urine. The stronger the “chlorine” smell, the more piss there is in that pool.
Try not to think about this the next time you go swimming. You could even argue that they’re basically little more than giant, swimmable, chlorine-filled toilet bowls. According to one study, there’s an average of eight gallons of pee in a typical 110,000-gallon pool. Considering the general size of the human bladder (which squeezes out around 300 milliliters per pee), that must mean the piss came from, at minimum, 100 different people.
All of this, of course, raises the question of what happens to all that pee, and the answer depends on whether the pool is ever totally drained. Everyone treats their pool differently: According to swimmer messageboard chatter about this sort of thing, public pools sometimes change their water twice a year; others do it every five years; and some never do it at all, because water is expensive and stuff.
But say a pool isn’t immediately drained: The short answer is, the pee goes nowhere! Instead, the chlorine changes the urine into different chemicals. Some of it turns to gas, (that’s the “eau de trichloramine” aroma), but it mostly turns to nitrate. And while nitrate makes good plant fertilizer, it does nothing for humans — except accumulate in a swimming pool until the water is completely replaced, that is.
Unsurprisingly, that swamp of chemicals isn’t so great: According to a study, all the stuff they use to treat pool water creates mutagens, aka stuff that could cause cancer. Called “disinfection byproducts,” or DBPs, they’re formed when swimming pool disinfectants mix with “human inputs” the stuff we refer to as piss, sweat, skin cells, you name it. Gross as it is, whether it’s actually dangerous is a matter of opinion.
