How Many Kids Could Pee in the Sprinkler?


Me and BRK at the pool at Grammie’s retirement community. Neither of us peed in it.

A few weeks ago BRK and I met up with another mom friend and her son at the park.  It was a hot day.  The kids played in the sprinkler setup — a 400-square-foot area with small sprinklers, large sprinklers, jets, fountains, even a rotatable water cannon.  The mom and I chatted, and watched.

“Mommy I have to use the potty!” Every mom knows those words, and I think every mom hopes it’s not her kid (unless, of course, one is engaged in potty-training).

It was BRK, and, as if scripted, I forgot to pack the portable potty.  Our toilet options were to go back home, a 10-minute walk and then an elevator ride up to the 14th floor, or a public bathroom a 15-minute walk away.  I wasn’t up for either of these options, especially with Baby Owl in tow.

“BRK,” I crouched down, “you know what? You can just go in the sprinkler.”

She looked up at me, unsure.

“Really, you can just go in your bathing suit, in the sprinkler, it’s fine.”

This is the chemist in me speaking.  I’m looking at the volumes of water gushing in this park, and thinking about the volume of a three-year-old pee event, and doing the dilution math.

Don’t worry, readers — my mom friend discouraged this.  “No, no, no,” she said, “don’t do that.”

I then felt self-conscious, realizing that not everyone sees the world as a collection of molecules, where the identity doesn’t matter as much as the dose.

She volunteered to keep an eye on Owl while I took BRK to the bushes behind the park and led her through her first squat.

I relayed this story to Eric the next night, and he asked mischievously, “The real question is, how many kids would it take to pee in the sprinkler before it’s contaminated?”

I’ve been tossing this question around in my mind, and so was delighted when some related calculations appeared in an article the WSJ last week.  The article is entitled, “Is That Pool Really Sanitary? New Chemical Approach Has Answers.

The article opens with a disturbing picture, stating that an artificial sweetener (acesulfame potassium) has been found in oddly high concentrations in Canadian swimming pools.  How did it get there? Pee.  The sweetener isn’t broken down in the body, and so is excreted through urine, and, when someone pees in a pool, into the pool.  Turns out acesulfame potassium is a star indicator of the prevalence of pool peeing.  Researchers were able to estimate that 0.01% of total pool volume studied (31 pools and hot tubs in recreational facilities and hotels in Canada) was contaminated by urine.  To put it a different way, about a half-teaspoon for every one hundred cups of water.  It’s nice to have some data on this, even if from only 31 Canadian pools, and moreover, to have a method.

The article then takes a darker turn, pointing out it’s not urine that should concern us, but feces.  The authors state:

“At any time, Dr. Hlavsa said, adults have about 0.14 grams of poop on their bottoms and children have as much as 10 grams.  ‘When you’re talking about bigger water parks with 1,000 children in a given day, you’re now talking about 10 kilograms or 22 pounds of poop.’ “

Pause for gagging.

This number definitely had an impact on me.  While my adult-onset swing nausea likely already ruled out future flume rides, this statement was the final nail in the coffin.

Coming back to the pools — researchers are concerned because since chlorine reacts with urine, less of it becomes available where needed: to disinfect poop that contains bacteria that can actually make one sick.

The article concludes with some best practices for pool use I am likely to follow. 1) The smell test.  Chlorinated pools give off a strong odor when urine is present, reacting with the chlorine.  A pool free from urine, and thus with chlorine able to do its job, should not smell.  2) Everyone should “shower for about one minute before swimming to remove personal care products and traces of feces.”

While this article did not answer my question on how many kids can pee in the sprinkler, it certainly got me thinking.  The feces bit becomes especially disturbing when we are talking sprinklers — is the sprinkler water chemically treated for that kind of contamination?

Here’s wishing you happy and human-waste-free summer water fun!