There’s nothing more refreshing than cooling off in the pool on a hot summer day. But as temperatures rise, pools and water parks tend to become more and more crowded with people.
Though chemicals in the water (like chlorine and bromine) kill many viruses and bacteria, there are still certain germs that may be lurking in the water — and it’s important to know what you can do to avoid them.
“You can get swimming-related illnesses … [from] water contaminated with germs,” explained Jasen Kunz, the healthy water program lead at the Centers for Disease Control and Prevention’s Waterborne Disease Prevention Branch.
Sickness can also result from “having contact with chemicals that are in the water or inhaling chemicals that evaporate … and turn into gas in the air,” Kunz noted.
Thankfully there are steps you can follow to significantly reduce your chances of getting sick from going in the water. We talked to experts about the most common illnesses people can pick up from the pool — and tips for avoiding them.
The most common cause of swimming-related illness outbreaks is diarrhea.
“This is one of the reasons why, if there is a fecal accident in a pool, there is protocol the lifeguards and pool operators follow before allowing people back into the water,” explained Dr. Clare Rock, an associate professor at the Johns Hopkins University School of Medicine.
Millions of germs can get into the water when someone with diarrhea has an accident, and other people can get sick by swallowing even a small amount, Kunz told HuffPost.
What’s more, someone doesn’t necessarily need to have an accident in the water for others to get sick. Small particles of poop can come off of people’s bodies while swimming, so you may not necessarily even see it in the water.
Some of the most common germs you might pick up include cryptosporidium, norovirus, giardia, shigella and E. coli, Kunz said. Depending on the pathogen, you might experience diarrhea, nausea, vomiting, fever or stomach pain as a result.
So why doesn’t the chlorine in the water kill these germs?
First of all, it’s critical that pools and water playgrounds have the correct amount of chlorine or bromine, and the correct pH, so they can effectively prevent the spread of germs, according to the CDC.
But “people can still be exposed to germs during the time it takes for chlorine to kill the germs,” explained Dr. Jessica Lum, an infectious disease specialist at Cleveland Clinic.
Cryptosporidium, also known as crypto, is particularly resistant to chlorine. According to one CDC report, it caused 49% of infectious outbreaks in aquatic venues like pools, hot tubs and water playgrounds from 2015-2019.
“[Usually] chlorine or bromine inactivates or kills germs in properly treated water within minutes,” Kunz said. “However, crypto … can survive for more than seven days.”
People who have weakened immune systems are more at risk of catching a severe crypto infection, so Rock recommended that they check with a health care provider before swimming.
You can also get an infection called swimmer’s ear.
“Swimmer’s ear is an infection caused by bacteria when pool water stays in the outer ear canal,” Rock explained.
When the water sits there for a long time, it “wears down protective wax and skin and provides a moist environment for bacteria to multiply,” according to the CDC.
This is most commonly seen in children, and it doesn’t spread from person to person. Symptoms include pain, itchiness, redness, swelling and drainage from the ear.
Chemicals in the water may irritate your eyes and cause rashes or coughing.
“Irritation may occur when chlorine in the pool turns into chemical irritants when combined with sweat, urine and dirt,” Rock said. “When you smell ‘chlorine’ at the pool, you are probably actually smelling these chemical irritants as they turn into gas in the surrounding air.”
These irritants, called chloramines, can cause red and itchy eyes, rashes, nasal irritation, coughing and wheezing, according to the CDC.
This is why it’s best to shower before going into the water and to never pee in the pool. Not only do chloramines form when pee, sweat or makeup combines with chlorine, but this also decreases the amount of chlorine that can get rid of other germs.
In addition to chloramines, improper pH levels in a swimming pool can lead to skin and eye irritation, Kunz said.
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But there are easy tips you can follow to avoid getting sick.
Here are some recommendations from experts who spoke to HuffPost, and from the CDC, on how to swim safely and prevent infection:
Scope out the pool or water park before you start swimming.
Looking at inspection reports for the swimming pool or water park ahead of time can be helpful for identifying any health or safety issues. These reports can usually be found at the venue or on the local health department’s website, Kunz said.
Before getting into the water, ask yourself these questions: Is the drain in the deep end of the pool visible? Does it appear to be secured and in good condition? Are there lifeguards on duty carefully observing the swimmers? If there aren’t lifeguards, do you see safety equipment, like a rescue ring?
Avoid bringing germs into the water.
You’ll often see signs at the pool that say to shower before getting in the water, and these shouldn’t be ignored.
“Rinsing off … for just one minute reduces most of the dirt or anything else on your body that uses up chlorine or bromine needed to kill … germs,” Kunz said.
Avoid getting poop in the pool, even the small particles that may be on your body. If you’ve been sick with diarrhea and were diagnosed with crypto, the CDC recommends waiting at least two weeks after it stops before swimming.
And no matter how convenient it may seem, don’t pee in the pool. While chemicals in the water generally kill any bacteria in pee, it still leads to chemical irritants forming, Rock explained.
If you’re swimming with babies or young kids, change diapers away from the pool to prevent contaminating the water with germs, Lum said. For kids who no longer wear diapers, make sure they take frequent bathroom breaks.
Take other precautions to minimize your risk.
One of the biggest things to avoid is swallowing the water. Also, stay out of the water if you have an open wound or cut, Lum said. If you do go in, the CDC suggests using a waterproof bandage to fully cover the wound.
“Tell a lifeguard if you see any feces in the water,” Rock said, adding that you should also alert a lifeguard to “any breathing, skin or eye irritation” you experience.
When you’re done swimming, completely dry out each ear to prevent swimmer’s ear.
“You can use a towel, but also pull the earlobe in different directions to drain out any water,” Rock said. “[And] consider using earplugs or a bathing cap to prevent pool water getting into the ear.”
Remember: Swimming can be done safely and also has many benefits.
Swimming has many benefits for both adults and kids, whether it’s reducing stress, boosting your mood or just being a great source of exercise.
“When considering any hobbies or activities, we balance the need for quality of life and [our] values with potential risk for infections,” Lum said, noting that you can still enjoy swimming as long as you implement “measures to minimize the risk of infection.”