One in five people admitted to peeing in a swimming pool, in a recent poll of Americans.

In fact, the survey conducted by the Water Quality and Health Council found that almost half (47 percent) of the subjects admitted to one or more behaviors that contribute to an unhealthy pool.

Here are some of the survey's other findings:

About one-third (35 percent) say they don't shower before entering the pool.

63 percent were unaware of illnesses associated with swallowing, breathing or having contact with contaminated pool water.

Less than one quarter consider the frequency of pool cleaning and chemical treatment (23 percent) and even less (16 percent) think about chlorine levels to maintain clean pool water.

"Swimming is a fun and healthy activity for old and young alike. Proper water chlorination helps protect swimmers from germs that can make swimmers sick," said Michele Hlavsa, an epidemiologist in the Division of Parasitic Diseases for the Centers for Disease Control and Prevention (CDC). "But swimmers also have role to play in maintaining a clean and healthy pool. Unhygienic behavior brings germs into the pool and makes it harder for chlorine to do its job.” The survey was conducted online between April 30 to May 3, 2009, among a national sample of 1,000 U.S. adults, using the field services of TNS Omnibus. Results were weighted to reflect the adult population based on U.S. Census figures, including age, gender, geographic region, household income and household size. The margin of error for the study was plus or minus 3.1 percentage points.

The Water Quality & Health Council is a body of independent scientific experts, health professionals and consumer advocates who serve as advisors to the Chlorine Chemistry Division of the American Chemistry Council, an industry trade association.

The CDC urges pool users to follow these six tips for healthy swimming:

Don’t swim when you have diarrhea.

Don’t swallow pool water.

Practice good hygiene. Shower with soap before swimming and wash your hands after using the toilet or changing diapers.

Take your kids on bathroom breaks or check diapers often.

Change diapers in a bathroom or a diaper-changing area and not at poolside.

Wash your children thoroughly (especially the rear end) with soap and water before they go swimming.

Unclean water can lead to recreational water illnesses (RWI’s) — diarrhea, respiratory illness, and ear and skin infections. Children, pregnant women and people with compromised immune systems can suffer from more severe illness if infected. According to the CDC, these illnesses are on the rise. Between 2005 and 2006, 78 outbreaks were reported in 31 states — the largest number of outbreaks ever in a two-year period. Close to 4,500 people were affected. To check that your public pool is properly chlorinated, the Water Quality and Health Council recommends the use of portable pool and spa testing strips, easily purchased at pool supply stores and discount retailers, in addition to trusting your basic senses. "A smelly pool is a dirty pool," said National Consumers League President Emeritus and Water Quality and Health Council Vice-Chair Linda Golodner. "Look for water that's clean, clear and blue. Check for tiles that feel smooth and clean. Make sure there are no strong odors. Listen for pool cleaning equipment. Using your senses help you recognize the difference between a healthy pool and one that needs cleaning and treatment."