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Heat Emergency in Boston
Mayor Wu announced a heat emergency in the City of Boston through Wednesday, July 17. Cooling centers will be open at 14 BCYF community centers Monday through Wednesday, from 9 a.m. - 5 p.m.
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Recreational Water Illness

This fact sheet answers frequently asked questions about recreational water illness.

Recreational water illnesses (RWIs) are infections caused by germs living in contaminated water.

The basics

What are recreational water illnesses (RWIs)?

You can find these germs in:

  • swimming pools
  • hot tubs
  • water parks
  • water play areas
  • interactive fountains
  • lakes
  • rivers
  • oceans

These germs can cause diarrhea or infection of the lungs, eyes, ears, stomach, skin, nose or throat.  

How are Recreational Water Illnesses (RWIs) Spread?

Swimmers not only share the water but the germs in it with every person who uses that body of water. On average, people have about 0.14 grams of feces on their bottoms. When that rinses off, it can contaminate the water. When someone is ill with diarrhea, their stool can contain millions of germs. This means that just one person with diarrhea can contaminate the water in a large pool or water park. Swallowing even a small amount of contaminated water can make you sick. 

Keep in mind that chlorine does not kill germs instantly. Some germs, such as Cryptosporidium (or "Crypto"), are extremely chlorine tolerant.

Steps for Healthy Swimming

Here are a few easy and effective healthy swimming steps all swimmers can take each time they swim to help protect themselves, their families, and their friends from recreational water illnesses:

Make sure the water is safe for swimming!

Keep an eye out for signs or posts that may indicate the water is not safe to be in! Water play areas such as interactive fountains or spray parks are becoming more common. People may not realize that these parks use recycled water. The spray water will rinse any contaminants down into the water holding area and re-spray them. As a result, it is possible for the water to become contaminated and make people sick.

Keep the pee, poop, sweat, and dirt out of the water!

  • Stay out of the water if you have diarrhea
  • Shower before you get in the water
  • Don't pee or poop in the water
  • Don't swallow the water

Every hour—everyone out!

  • Take kids on bathroom breaks
  • Check diapers, and change them in a bathroom or diaper-changing area–not poolside–to keep germs away from the pool
  • Reapply sunscreen
  • Drink plenty of fluids

Additional tips to protect yourself and others from RWIs:

  • Proper maintenance of chlorine and ph levels of pools, spas, hot tubs, and fountains can limit the spread of germs
  • Limit the amount of food to beaches or other recreational water sites. Don’t feed animals and birds that can leave droppings
  • Dispose of garbage properly especially diapers and other soiled materials
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