Looking to beat the heat this summer? Odds are, you’ll opt for a dip in the cool waters of a swimming pool. But you might want to think twice before diving in. Public pools can be hotbeds for all kinds of parasites, viruses, and bacteria—even when they are regularly treated with chlorine and other disinfectants.
In fact, thousands of Americans may get sick this summer due to contaminated water at pools, spas, or other recreational venues, according to a 2018 report by the U.S. Centers for Disease Control (CDC). “Germs commonly spread by water can cause diarrhea in people who swallow contaminated water,” according to Michele Hvalsa, chief of the CDC’s Healthy Swimming Program. Swimming in dirty pool water can also lead to infections and even drowning. Watch out for these hidden pool dangers, too.
Yet most people won’t get sick by diving into the average neighborhood pool, the CDC report found. It assessed 493 disease outbreaks caused by treated recreational water in the United States and found that hotel pools were by far the dirtiest. One in three swimming-related disease outbreaks between 2000 and 2014 occurred at a hotel, according to the report.
One of the most common culprits was Cryptosporidium, a parasite found in the fecal matter of someone who has diarrhea that can survive for days in chlorinated pools, per the CDC. It spreads when swimmers swallow contaminated pool water, leading to an unpleasant bout of diarrhea. That’s not the only surprising way your pool makes you sick.
Pseudomonas, bacteria that causes swimmer’s ear or “hot tub rash,” was responsible for nearly half of the hotel-related outbreaks. Also high on the list was Legionella, which can cause a severe case of pneumonia and is contracted by inhaling infected microscopic water droplets, according to the Mayo Clinic.
The next time you find yourself swimming in a hotel pool, take a few precautions to keep you and your fellow pool-goers healthy. The CDC recommends staying out of the water if you have diarrhea or an open wound, keeping your ears dry after swimming, and avoiding swallowing the pool water. And don’t ignore these red flags a public pool is too dirty for swimming.