Summertime PSA: Public pools are poop-filled and disease-ridden

Colin Lalley 1600


Colin Lalley

Colin Lalley

Insurance Expert

Colin Lalley is the Associate Director of SEO Content at Policygenius in New York City. His writing on insurance and personal finance has appeared on Betterment, Inc, Credit Sesame, and the Council for Disability Awareness.

Published May 25, 2017|4 min read

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This article comes with a spoiler warning. As in, it might spoil your appetite, so if you’re reading this around lunchtime, be careful.

Summer is the perfect time to jump in a swimming pool to cool off. It’s also a great way to keep the kids busy, and provides everyone with some much-needed physical activity. And since not all of us are lucky enough to own our own pools, families flock to public pools every year. But since the week in May before Memorial Day is apparently Healthy and Safe Swimming Week, the CDC has come out with an important announcement:

Poop in swimming pools can make you very, very sick.

Gross, right? But also important! The CDC’s warning is centered mainly around Cryptosporidium, aka Crypto. Thirty-two reports of Crypto reported in 2016 were traced back to swimming pools or water playgrounds, up from 16 in 2014. It’s not a lot,’s enough to make you think twice about jumping in a pool.

Crypto can make people sick for up to three weeks, and symptoms include diarrhea, stomach cramps, nausea, or vomiting – all of which can contribute to dehydration. When it comes to pools, it’s transmitted by people inadvertently drinking pool water that has fecal material in it, and just one mouthful can make you sick. And since "people have about 0.14 grams of feces on their bottoms" (who knew?) it’s not uncommon for it to wash off in a pool. If you’re sick, you risk getting others sick, too.

"But don’t pools have chlorine that kills bad things?" you manage to ask without vomiting while thinking about poop in pools.

It does! And that works great for other recreational water illnesses (RWIs). E. coli dies in less than a minute in chlorinated water; Hepatitis A dies in 16 minutes. But the Crypto parasite stays around for over 10 days in chlorinated water. The CDC recommends hyperchlorination for handling Crypto outbreaks, which is what it sounds like: dumping high levels of chlorine into pools.

But even that isn’t enough to keep us safe. According to the CDC, a 2010 study found that one in eight public pools were closed after inspections found "serious code violations such as improper chlorine levels."

The CDC is so committed to battling Crypto that it developed CryptoNet, "a multidisciplinary, molecular-based surveillance system built on the common BioNumerics platform successfully used by PulseNet and CaliciNet...aimed at the efficient use of existing infrastructure to facilitate the systematic collection and molecular characterization of Cryptosporidium isolates to further understand cryptosporidiosis epidemiology." If that sounds like something out of a big-budget science fiction blockbuster about a devastating CDC outbreak, that should tell you how serious the situation is.

Or is it?

Truthfully, Crypto-via-public-pool is something of an outlier. There are other more common RWIs, like E. coli, but they’re more easily killed by chlorine. And diarrhea is the only real danger for passing on Crypto in pools; "formed fecal matter" hasn’t been found to transmit the parasite, so it’s not like all poop will get you sick (was that comforting?).

And consider the small number of pool incidents that make up the total Crypto cases. From July to October 2016, there were 352 cases of Crypto. Ohio had 1,940 cases in total in 2016. Those are huge increases from previous years – from 2011 to 2015 Arizona had at most 62 cases in a year, and Ohio’s maximum number of cases was 571 – but public pools were only responsible for 32 outbreaks were reported in the entire country in 2016. We still need CryptoNet, but we probably don’t have to be too afraid of public pools.At least when it comes to Crypto. There are plenty of other reasons to be wary of public pools: screaming kids and rogue cannonballs, the fact that the average public pool has eight gallons of pee in it, and the fact that we clean our pools with chlorine and other chemicals that are dangerous to humans as well as germs.So what’s a parent to do when the summer heat becomes unbearable and all you want is for your kids to swim around, cool off, and tire themselves out? Well, you can still take them to the pool – and take the proper precautions. The CDC offers a few suggestions, like:

  • Stay out of the pool if you’ve had diarrhea within the past two weeks.

  • Don’t drink pool water.

  • Rinse off in the shower before entering a pool (and shower after).

  • Don’t skimp on the bathroom breaks!

They also provide safety guidelines for pool staff.

So remember,the next time you reenact that hilarious Caddyshack poop bit, keep in mind that there are real consequences to poop in pools. It’s all fun and games until someone gets Crypto.