Mind & Body

The Scientific Reason You Shouldn't Pee in the Pool (And You Should Shower Before Swimming)

Swimming is good, clean, summer fun. When we say "clean," we mean that in the wholesome sense, not the sanitary one. Sorry to burst your bubble, but commercial swimming pools are flooded with urine. Though you hopefully know not to pee in the pool (come on), you're probably committing another serious pooltime crime without even realizing it.

We All Put the "P" in Pool

We don't care what you tell us — the data says that you're probably, definitely peeing the pool. Everyone does it, pretty much. In a 2017 study, scientists found that the average commercial swimming pool contains about 20 gallons of urine. They determined this by measuring levels of artificial sweetener in swimming pools. These sweeteners are designed to go right through you and are not easily broken down by chlorine.

"I think you can assume that if people are using your pool, they're peeing in it," Ernest Blatchley III, an environmental engineer at Purdue University, tells NPR. "I view it like secondhand smoke. It's disrespectful and potentially dangerous." Besides just being objectively gross, pee-filled pools pose certain health risks.

Shower Power

Not showering before swimming exacerbates the problem caused by pee in pools. Surely, you've seen signs at public swimming holes recommending (or even demanding) a pre-swim rinse-off. No judgment if you've never done it yourself; it seems counterproductive, no? According to a survey, about 44 percent of adults skip the showers before swimming. Pools have chlorine in order to kill germs, but the organic compounds you're adding to the mix create a whole new set of problems. Sorry.

The chlorine in pools interacts with organic compounds like sweat, lotion, sunscreen, and (duh) urine to create "disinfection byproducts" like chloramines, cyanogen chloride, and nitrosamines. These byproducts can irritate the skin, eyes, and the respiratory tract, according to the CDC.

Don't blame chlorine alone; eyeball redness after a summer dip is caused by these byproducts, by the way. These irritants can be airborne, too. This is why proper ventilation is an important requirement for indoor pools and waterparks. We found that one out the hard way in 2015, after patrons at an Ohio waterpark started experiencing some undesirable side effects (eye burning, nose irritation, difficulty breathing, and vomiting) from the ill-ventilated resort.

The takeaway? Don't pee in the pool, for goodness sake, and take even just a one-minute rinse before setting foot on the high dive, too.

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The swimming pool has a fascinating role in American history. Learn all about it in "Contested Waters: A Social History of Swimming Pools in America" by Jeff Wiltse. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Joanie Faletto November 13, 2017

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