healthHealth and Medicine

A Grim Amount Of People Pee In The Pool – Here's Why You Shouldn't


Tom Hale

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist

Girl in swimming pool.

Aside from the obvious grossness, there is a good reason why you should save your urine for the bathroom. Image credit: Jaruwan Jaiyangyuen/

Fess up: who has been peeing in the pool?

Though few would publically admit to committing the deed, there’s plenty of evidence to show that most (if not all) public swimming pools are filled with significant amounts of human urine. Grossness aside, there are a few good reasons why pee-packed pools are not a good idea. 

How much pee is in a pool?

A study published in the journal Environmental Science & Technology Letters sifted through water samples taken from 31 pools and hot tubs in two Canadian cities, finding evidence of urine in every sample. As per their findings, the average 1,000,000-litre (220,000-gallon) swimming pool contains around 90 liters (20 gallons) of pee.


So, who's responsible? Apparently, quite a few of you. In one survey, at least 19 percent of adults admitted to having urinated in a swimming pool. Adults. Not kids. Another survey put that figure as high as 40 percent. Some of the worst offenders may even be professional swimmers – according to Carly Geehr, former USA Swimming National Team Member, nearly 100 percent of elite competitive swimmers pee in the pool. 

“Regularly. Some deny it, some proudly embrace it, but everyone does,” Geehr wrote in a Quora post.

Is pee sterile?

Despite what you may have heard, urine is not sterile. Even if you don’t have a urinary tract infection or a bladder infection, pee is naturally home to low levels of bacteria.

One 2015 study found an average of 5.8 bacterial species in females and 7.1 in males. Many of these species are likely to be “good bacteria” that even may help play a role in healthy bladder function


Guzzling tiny sips of pee from a swimming pool is unlikely to make you sick. However, aside from the obvious grossness, there is a good reason why you should save your urine for the bathroom. 

How bad is it to pee in a pool?

The CDC explains that urinating in a pool leaves less chlorine available to kill germs that could actually make you sick. Furthermore, uric acid in urine can interact with chlorine in the water, potentially generating hazardous airborne chemicals. One of these byproducts is cyanogen chloride, a toxic compound that’s literally used as a chemical weapon in warfare. The amounts of these chemicals produced in a pool are not going to kill you, but it's certainly enough to give you red and stinging eyes. 

In 2020, a chemical warfare expert shared his experience of receiving a phone call from the White House regarding a sample of swimming pool water from Las Vegas. A huge amount of metabolites for human urine were discovered, obviously, but there was also clear evidence of poop (both human and animal), plus trace amounts of drugs including cocaine, ketamine, and several different opiates.

Pee, it seems, maybe the least of your worries if you're taking a dive into a busy swimming pool. 


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