Diarrhea and Swimming
When someone swallows contaminated recreational water—water in pools, hot tubs, water playgrounds, or oceans, lakes, and rivers— they can get sick with diarrhea. In fact, diarrhea is the most common illness spread through recreational water.
Which germs in recreational water cause diarrhea?
Diarrhea can be caused by germs such as Crypto (short for Cryptosporidium), Giardia, Shigella, norovirus, and E. coli O157:H7. Some of these germs can survive in properly chlorinated water for almost an hour, or even days.
Tiny amounts of poop are rinsed off swimmers’ bottoms as they swim through the water. If someone with infectious diarrhea (which can contain up to one billion germs) gets in recreational water, germs can be washed off their bottom and contaminate the water. These germs can make someone else sick if they swallow even a small amount of contaminated water.
In public pools, water playgrounds, and hot tubs, disinfection of the water (with chlorine or bromine) and filtration work together to help kill germs. Chlorine and bromine kill most germs within minutes, and filters remove debris (e.g., leaves, sticks), which use up the needed chlorine or bromine. Swimmers may still be exposed to germs during the time it takes for the chlorine or bromine to the kill germs or for the water to be recycled through filters. And certain germs, like Crypto, can stay alive for days, even in pools with proper filtration and disinfection.
Many facilities use one filtration system for multiple pools, which causes water from multiple pools to mix. This means germs from one person’s body could contaminate the water in multiple pools.
How do I protect myself and those I care about?
We all share the water we swim, play, or relax in, so each of us plays a key role in helping to protect ourselves, our families, and our friends from germs that can cause diarrhea.
All of us can take the following healthy swimming steps:
- Stay out of the water if you are sick with diarrhea.
- If you have been diagnosed with Crypto, don’t go back in the water until 2 weeks after diarrhea has completely stopped.
- Use test strips to make sure the water has a proper free chlorine (amount of chlorine available to kill germs) or bromine level and pH.
- Free chlorine level: at least 1 part per million (ppm) in pools and water playgrounds and at least 3 ppm in hot tubs.
- Bromine level: at least 3 ppm in pools and water playgrounds and at least 4 ppm in hot tubs.
- pH (affects how effectively germs are killed or inactivated): 7.2–7.8.
- Most superstores, hardware stores, and pool supply stores sell test strips. Follow the manufacturer’s directions to ensure proper usage.
- Shower before you get in the water.
- Rinsing off in the shower for just 1 minute removes most of the dirt or anything else on your body that uses up chlorine or bromine needed to kill or inactivate germs.
- Don’t poop in the water.
- Don’t swallow the water.
- Take kids on bathroom breaks and check diapers every hour.
- Change diapers away from the waterside to keep germs from getting in the water.
Follow these and other steps for healthy swimming to help protect you and those you care about from recreational water illnesses.