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What are Recreational Water Illness (RWIs)?
RWIs are illnesses that are spread by swallowing, breathing, or having contact with contaminated water
from swimming pools, spas, lakes, rivers, or oceans. Recreational water illnesses can cause a wide variety
of symptoms, including gastrointestinal, skin, ear, respiratory, eye, neurologic and wound infections.
The most commonly reported RWI is diarrhea.
Diarrheal illnesses can be caused by germs such as Crypto, short for Cryptosporidium, Giardia, Shigella,
norovirus and E. coli O157:H7.
Where are RWIs found?
RWIs can be spread through use of swimming pools, hot tubs, decorative water fountains, oceans, lakes,
Swimming Pools, Waterparks, Spray Features
The most common illness spread through use of swimming pools is diarrhea. If swimmers are ill with diarrhea,
the germs that they carry can contaminate the water if they have an "accident" in the pool. On average,
people have about 0.14 grams of feces on their bottoms which, when rinsed off, can contaminate recreational
water. When people are ill with diarrhea, their stool can contain millions of germs. Therefore, swimming
when ill with diarrhea can easily contaminate large pools or waterparks. As a result, if someone swallows
water that has been contaminated with feces, he/she may become sick. Many of these diarrhea-causing germs do
not have to be swallowed in large amounts to cause illness. Remember that standing water is not necessary
for RWIs to spread so even spray decks can become contaminated (the water is just in a collection tank
underground) and spread illness. To ensure that most germs are killed, chlorine or other disinfectant
levels and pH should be checked regularly as part of good pool operation.
Skin infections like "hot tub rash" are the most common RWIs spread through hot tubs and spas.
Chlorine and other disinfectant levels evaporate more quickly because of the higher temperature of the water
in the tubs. Respiratory illnesses are also associated with hot tub use if the hot tub is not well
maintained. Because of this it is important to check disinfectant levels even more regularly than in
swimming pools. "Hot tub rash" can also be spread in pools and at the lake or beach.
Decorative Water Fountains
Not all decorative or interactive fountains are chlorinated or filtered. Therefore, when people,
especially diaper-aged children, play in the water, they can contaminate the water with fecal matter.
Swallowing this contaminated water can then cause diarrheal illness.
Lakes, Rivers, and Oceans
Lakes, rivers, and oceans can become contaminated with germs from sewage, animal waste, water runoff
following rainfall, fecal accidents, and germs rinsed off the bottoms of swimmers. It is important to avoid
swallowing the water because natural recreational water is not disinfected. Avoid swimming after rainfalls
or in areas identified as unsafe by health departments. Contact your state or local health department for
results of water testing in your area or go to EPA's beach site or their National Health Protection
Survey of Beaches.
How are RWIs spread?
Keep in mind that you share the water with everyone else in the pool, lake, or ocean.
If swimmers are ill with diarrhea, the germs that they carry can contaminate the water if they have an
"accident" in the pool. On average, people have about 0.14 grams of feces on their bottoms which, when
rinsed off, can contaminate recreational water. When people are ill with diarrhea, their stool can
contain millions of germs. Therefore, swimming when ill with diarrhea can easily contaminate large pools
or waterparks. In addition, lakes, rivers, and the ocean can be contaminated by sewage spills, animal
waste, and water runoff following rainfall. Some common germs can also live for long periods of time in salt
water. So, if someone swallows water that has been contaminated with feces, he/she may become sick.
Many of these diarrhea
-causing germs do not have to be swallowed in large amounts to cause illness.
Many other RWIs (skin, ear, eye, respiratory, neurologic, wound, and other infections) are caused by germs
that live naturally in the environment (water, soil). In the pool or hot tub, if disinfectant is not
maintained at the appropriate levels, these germs can increase to the point where they can cause illness
when swimmers breathe or have contact with water containing these germs.
Why doesn't chlorine kill these RWI germs?
Chlorine in swimming pools does kill the germs that may make people sick, but it takes time.
Chlorine in properly disinfected pools kills most germs that can cause RWIs in less than an hour.
Chlorine takes longer to kill some germs such as Crypto, which can survive for days in even a properly
disinfected pool. This means that without your help, illness can spread even in well-maintained pools.
Healthy swimming behaviors are needed to protect you and your family from RWIs and will help stop germs
from getting in the pool.
Protect Yourself from Recreational Water Illnesses by:
Look at the pool and surroundings. What should you notice?
Ask questions of the pool staff.
- Clean and clear pool water; you should be able to clearly see any painted stripes and the bottom of
- Smooth pool sides; tiles should not be sticky or slippery.
- No odor; a well-chlorinated pool has little odor. A strong chemical smell indicates a
- Pool equipment working; pool pumps and filtration systems make noise and you should hear them
Act by being proactive and educating others.
- What specialized training did the staff take to prepare for working at or operating the pool?
- Are chlorine and pH levels checked at least twice per day?
- Are these levels checked during times when the pool is most heavily used?
- Are trained operation staff available during the weekends when the pool is most heavily used?
- What was the health inspector?s grade for the pool after its last inspection?
Practice healthy swimming behaviors
- Learn about recreational water illnesses and educate other users and your pool operator.
- Urge your pool management to spread the word about RWIs to pool staff and pool users.
- Let your pool operator know that the health and well being of all swimmers is a priority for you.
- Check the pool water yourself for adequate chlorine (1-2 parts per million) and pH (7.2-7.8)
levels. Pool and spa chlorine test strips are available at local home improvement stores,
discount retailers and pool supply stores. If you want to practice using them at home,
Safety is always important.
- Refrain from swimming when you have diarrhea.
- Avoid swallowing pool water or even getting it in your mouth.
- Shower before swimming and wash your hands after using the toilet or changing diapers.
- Take children on bathroom breaks or check diapers often.
- Change diapers in a bathroom and not at poolside and thoroughly clean the diaper changing area.
- Keep an eye on children at all times, kids can drown in seconds and in silence.
- Don't use air-filled swimming aids (such as "water wings") with children in place of life
jackets or life preservers.
- Protect against sunburn by using a sunscreen with at least SPF 15 and both UVA and
UVB protection, and be sure to re-apply it after swimming.
Source: Department of Health and Human Services, Centers for Disease Control and Prevention
Adapted by Editorial Staff, June 2007
Last update, August 2008