Researchers have found a way to determine just how much urine there is in a pool.

family swimming underwater
Credit: YanLev/Shutterstock

When I was growing up, my next-door neighbor had a pool with a big sign that read: "Welcome to our OOL. Notice there's no P in it? Please keep it that way." Hilarious, right? Or at least it was as a kid. Because now that I'm an adult, the thought of kids—or anyone, for that matter—peeing in a pool is just gross. But it looks like the joke's on me. Because as it turns out, there was P in my neighbor's OOL—at least according to a new study that just revealed that every pool has a little bit of pee in it.

Wait, what?

That's right—researchers in Canada sampled more than 30 pools (admittedly, not a large sample) and found pee in every single one of them. Ewwwww! Wondering how they did it? They measured the levels of something called acesulfame potassium (ACE), which is found in many processed foods and later excreted through urine in its original form. By measuring it, the researchers could estimate the amount of pool water that was actually pee.

But before you start freaking out, there is a silver—golden?—lining of sorts. While the study revealed urine in every sample tested, the levels were relatively low, coming in at only 0.00009 percent. You might want to skip the Jacuzzi, however, since the researchers also tested samples from eight hot tubs—including those at hotels—and found the levels of ACE to be way more pee-saturated than the readings from the swimming pools.

And pee in a swimming pool isn't just straight-up disgusting, it's also potentially harmful, since it can react with chlorine to create toxic compounds that irritate the eyes and lungs. Still, the researchers say the goal of the study was not to condemn swimming, but simply to implore the public to refrain from putting anymore P in the OOL.

So just don't do it, OK?

Hollee Actman Becker is a freelance writer, blogger, and mom of two who writes about parenting and pop culture. Check out her website for more, and then follow her on Instagram and Twitter