Ladies and gentlemen, we have an epidemic of aquatic proportions on our hands: one out of five people freely admit to peeing in our pools. Even Michael Phelps and Ryan Lochte have gone on record stating they frequently pee in pools. But it’s not their fault; in fact peeing in the pool is a physiologic response to being in the water.
The water’s increased pressure on your immerged body (as compared to air) increases your fluid volume in circulation. One (of many) mechanisms to remove excess fluid from circulation is a peptide called Brain Natriuretic Peptide, BNP, (actually released in the heart), that likely along with its counterpart Atrial NP causes the kidney to “filter” out more water reducing the circulating volume, thus producing more urine. This is your body’s mechanism of reducing the amount of work the heart has to do in response to more fluid in circulation.
But is peeing as bad it’s made out to be, well Stuart Jones, senior biochemist at Sense About Science , a London-based association, doesn’t seem to think so. “Peeing in a swimming pool [sic] has very little impact on the composition of the pool water itself.” He continues that “Urine is essentially sterile so there isn´t actually anything to kill in the first place… [it’s] largely just salts (ammonia) and water with moderate amounts of protein and DNA breakdown products.” The oxidizers (e.g. chlorine) prevent that urine expelled bacteria from prorogating in the pool water. From a volumetric analysis, an average lap pool has almost a half million liters (130,000 gallons) of water and a single urination produces only 0.2 liters. You’d need a LOT of urine to affect the pool chemistry.
From an industry perspective, organic loadings have always been a concern for chloramine development leading to over chemical laden pools. As a preventative measure aquatic staff has told patrons urine changes the color of the water. I hate to be the bearer of bad news, but there is no such chemical additive to the pool; it’s even Snopes verified. But that hasn’t stopped comedians or pop culture from seizing hold.
So what's the big deal with peeing in the pool? Well from a sanitation concern there really isn't one, but from a health and comfort concern peeing may be the number one problem. So for all those swimmers out there who complain about red-eyes in the pool, first STOP COMPLAINING ... YOU'RE THE PROBLEM! Second, stop peeing in the pool and making it worse for everyone else.