So, how much pee is actually in that pool? Turns out -- maybe gallons of it.

Before you execute your next cannonball in Neighbor Bob's pool, consider this -- you could be splashing around with two or three gallons of Neighbor Bob's urine. Yum.

Blame this oh-so-inconvenient truth on researchers in Alberta, Canada.

They figured out a way to measure pee in pools: by way of an artificial sweetener found in everything from soup to soda. It passes right through the body, in the urine. And into the pool.

The intrepid research team collected water samples from dozens of pools in Canada. Based on the concentrations of artificial sweetener they found, they determined how much urine was in each pool.

Among their findings: a public pool measuring one-third the size of an Olympic pool usually contained about 17 gallons of pee. That's a lot of oh-doesn't-that-feel-better.

An Olympic-size pool? Up to 50 gallons of tinkle. (Enough to tarnish all those Michael Phelps gold medals)?

These volumes appear too great to pin solely on the kindergarten set. In fact, surveys show at least one in five adults admits to letting go in the pool.

So yeah, it's gross. But is it harmful? The answer is... eh.

Pee is actually sterile. But pee contains chemicals that can react with pool water to create a toxic byproduct. Get enough of it down your gullet or in your eyes over a long period of time, and you might have a problem.

The Canadian researchers say they don't want to scare anybody out of the pool with this study. Rather, they strongly suggest that when nature calls, go to the restroom before you answer.