Recreational Water Illnesses

Swimming pools, spas, lakes, rivers, or oceans are all potential sources of water recreation illness. Recreational water illnesses typically affect a person's stomach and intestines, skin, or respiratory system.

If you think you have a recreational water illness that needs medical attention, contact your health care provider. Report suspected recreational water illnesses to your local health department. If you can't reach them, contact us at 206-418-5500 (24-hour assistance available). Health care providers, hospitals, and local health departments are required to report waterborne disease outbreaks.

Stomach and Intestinal Illness

Gastrointestinal illnesses affect a person's stomach and intestines, and can cause diarrhea, nausea, or vomiting. The following gastrointestinal illnesses have been associated with recreational water activities.

Cryptosporidium (Crypto)

Crypto has become one of the most common causes of water recreation diarrhea illness in the United States. The germ is found in people's stool. It's highly resistant to chlorine disinfection and can survive in a pool for as long as ten days. Swallowing contaminated water is how people are often infected. To help stop the spread of Crypto, people with diarrhea shouldn't go swimming. Learn more at Crypto, CDC.


Giardia is another common cause of diarrhea and is found in infected people's stool. It can take about 45 minutes for this germ to be killed by chlorine disinfection in pools. You shouldn't swim if you have diarrhea and you should always avoid swallowing water while swimming. Learn more at Giardia, CDC.


Shigella causes severe diarrhea, which is often bloody. It can be spread if an infected person with diarrhea swims or plays in areas such as beaches or inadequately disinfected pools. Having hand washing stations with soap near swimming areas helps keep the water from becoming contaminated. Daycare centers shouldn't provide water play areas. Learn more at Shigellosis, CDC.

E. coli O157:H7

People have gotten an E. coli infection by swallowing lake water while swimming. Symptoms are similar to Shigella and include severe diarrhea and bloody stool. This infection can also be life-threatening and cause permanent damage to the kidneys. Swimming in inadequately disinfected pools or contaminated beaches are potential sources of infection. Learn more at E. coli, CDC.


Noroviruses are very contagious and can spread through an infected person's stool or vomit. The illness often begins suddenly and usually includes nausea, vomiting, diarrhea, and stomach cramps. Chlorine disinfection helps kill this virus in pools, but lakes and beaches can be contaminated. Avoid swallowing water while swimming to help prevent infection. Learn more at Norovirus, CDC.

Skin Irritations

Skin rashes, boils, allergic reactions to chemicals, and skin damage from the sun can occur when enjoying water recreation activities.

Hot Tub Rash - Pseudomonas dermatitis / Folliculitis

Hot Tub Rash or dermatitis is an infection that causes an itchy bumpy rash on the skin. The rash usually occurs within days of swimming in poorly maintained hot tubs or spas but can also be spread by swimming in a contaminated pool or lake. Properly maintaining hot tubs and pools helps eliminate the germ that causes this rash. Learn more at Hot Tub Rash, CDC.

Swimmer's Itch - Cercarial dermatitis

Swimmer's itch is a rash caused by an allergic reaction to parasites that typically infect some birds and mammals. The parasites come from infected snails which live in lakes, ponds, and oceans. People are not suitable hosts for the parasite's life cycle, so after burrowing into a swimmer's skin, the parasite soon dies. Reduce your risk by not swimming in area's known to have a swimmer's itch problem or where snails are commonly found and showering or towel drying immediately after leaving the water. More tips on reducing the risk and treating swimmer's itch are at Swimmer's Itch, CDC.

Swimmer's Ear - Otitis externa

Swimmer's ear is an infection of the outer ear canal and can affect anyone but is most common in children. Symptoms usually start a few days after swimming and include ear pain, itchiness, redness, swelling, and pus draining from the infected ear. It can be treated with antibiotic ear drops. Swimmer's ear is caused when water stays in the ear canal for long periods of time, allowing germs to grow and infect the skin. When swimming, try to keep ears dry. If water gets in your ear, tilt your head with ear facing down and gently pull your earlobe in different directions to help the water drain out. Learn more at Swimmer's Ear, CDC.

Cyanobacteria - Blue-green Algae

Cyanobacteria, also called harmful algal blooms or blue-green algae, are found in lakes, rivers, ponds, and seawater. Sometimes cyanobacteria is toxic and people can experience skin, eye, or ear irritation with contact. If toxic cyanobacteria is swallowed, it can cause stomach cramps, vomiting, diarrhea, sore throat, fever, headache, muscle and joint pain, or nerve and liver damage. Avoid swimming in or having contact with algal blooms. Don't let pets drink or swim in waters with algal blooms. Learn more about Blue-Green Algae.

Chemical Sensitivity

Some people can experience allergic reactions, such as skin redness and itching, to chemicals used in pools. The reactions commonly occur within an hour or two of being in the water. It's also possible that improper use of chemicals or a chemical release at a pool could expose people to skin or respiratory irritants.

Sun Exposure

Prevent sun burns and skin cancer by choosing five protection options: seeking shade, covering up, getting a hat, wearing sunglasses, and rubbing on sunscreen. Learn more at Skin Cancer, CDC.

Respiratory Illness

Some water recreation illnesses can affect a person's breathing causing cold or flu-like symptoms, shortness of breath, cough, or a serious infection in the windpipe or lungs.


Legionnaire disease is a serious infection that creates life threatening pneumonia. Another less serious form of the infection is Pontiac fever, which has the same early symptoms of Legionnaire disease (body pain and weakness, headache, fever, chills, and cough) but isn't associated with pneumonia or death. The germ that causes the disease can be found in streams, ponds or in man-made structures such as fountains or spas. People are typically infected by breathing in contaminated water vapor or steam. Proper maintenance of pools and spas helps eliminate this germ. Learn more at Legionellosis, CDC.

Mycobacterium avium & endotoxins

Water vapor or steam contaminated with bacteria or bacterial fragments can be breathed in causing an allergic reaction and inflammation in the lungs. This condition, called "hypersensitivity pneumonitis," is rare, but has been associated with spas or indoor pools that have water features that produce vapors or mists. Water sitting in pipes that isn't continuously disinfected can become a source of bacterial fragments. Proper maintenance of pools and spas helps eliminate these germs.

In the Swim of Things Video

More Resources

Water Recreation - Beach swimming advisories, staying safe in pools and open water, and regulated water recreation facility resources.

Healthy Swimming, CDC

Content Source: Water Recreation Program