Think a chlorinated pool is a safe, sterile place? Think again. There are a few dangers lurking in a shared pool, whether at a gym, a community center or even a fancy resort. In fact,  outbreaks of illnesses from hot tubs and pools have been increasing in recent years, with 90 outbreaks causing 1,788 illnesses and one death between 2011-2012, according to a new report from the Centers for Disease Control and Prevention. Learn what icky things you can pick up, plus how to ward them off.

Diarrhea

One of the top causes of post- swim illness is a parasite called cryptosporidium (crypto for short), which leads to diarrhea, stomach pain and nausea. According to the new CDC report, of the 69 outbreaks associated with treated water, more than half were caused by crypto.  Symptoms can last for up to two weeks. The parasite ends up in the water if feces (even trace amounts from someone who didn’t shower first) of an infected person gets in the pool. The bug is resistant to chlorine and survives outside the body for long periods.

Protect yourself: Crypto spreads when you accidentally swallow contaminated pool water or you touch your mouth before washing your hands. Don’t touch your face until you’ve had your post-swim shower, with soap and hot water.

Pinkeye

Burning eyes, excessive tearing and redness can occur because of an allergic reaction to chlorine, or an infection if the pool isn’t chlorinated enough. It can also happen if people aren’t showering before swimming or are (ugh!) peeing in the pool. Urine, as well as cosmetics and other chemicals that can wash off people’s skin, can irritate your eyes.

Protect yourself: You can shield your eyes from all of this by wearing a pair of well-fitting goggles every time you go for a dip.

Hot Tub Rash

This is an itchy skin infection that can lead to a bumpy, red rash, often worse in the areas covered by your bathing suit. Chlorine can easily kill the germ that causes it, but the warm water in a hot tub makes chlorine break down faster, so it’s more likely you’d pick it up there.

Protect Yourself:  The risk of hot tub rash goes up the longer the contaminated water touches your skin, which is why it seems to show up in areas your wet bathing suit clings to. Save your dip in the hot tub for the end of your pool day, shower and change shortly after your soak and wash your swimsuit before wearing it again.

Health's medical editor, Roshini Rajapaksa, MD, is assistant professor of medicine at the NYU School of Medicine and co-founder of Tula Skincare.

Contributed reporting by Amelia Harnish.

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