Pool season is upon us, and public swimming pools are open. So come on in. The water’s warm.

Maybe a little too warm.

A new national survey finds that 17 percent of American adults admit they urinate in the pool.

And nearly eight in 10 adults are convinced that other swimmers are doing it, even if they don’t themselves.

“I don’t know if I would anticipate that the numbers would be that high, but it’s something that happens,” said Tony Cosby, who oversees one indoor and six outdoor pools in Overland Park, Kan.

While there’s a major yuck factor in feeling a warm current in a cool pool, the real health danger comes elsewhere, according to the U. S. Centers for Disease Control and Prevention. The CDC is working with the Water Quality and Health Council, which sponsored the survey, to encourage good pool hygiene.

Among those dangers: Kids with dirty diapers. Diapers changed at poolside. Adults with intestinal complaints.

Fecal particles can carry bacteria such as strep, staph and salmonella, and viruses like hepatitis, said Bert Malone of the Kansas City Health Department. You can pick up the germs by swallowing pool water.

In recent years, outbreaks of cryptosporidiosis, a nasty diarrheal illness, have centered on swimming pools and recreational water parks from Salt Lake City to Charleston, S. C.

In some locales, people admitted to health investigators that they went swimming even when they had symptoms.

Malone doesn’t want to scare people out of the pool.

Chlorine and sunlight are effective at killing germs in the water, he said. “But they’re clearly not 100 percent. There’s always a risk.”

Another preventive measure is a soapy shower before diving in.

“That was a requirement when I was a kid,” Malone said. “I don’t see that happening much anymore, frankly.”

The new survey bears that out: 35 percent of adults say they don’t shower before getting in the water.

The number who shirk the shower is likely much higher, said Linda Golodner of the National Consumers League. “I think some people have bent the truth here and don’t want to admit it,” she said.

Golodner is vice chairwoman of the water quality council. Her panel of health experts advises the American Chemistry Council, an industry trade association, on food and water safety.

At Overland Park pools, chlorine levels are checked every hour and the water is thoroughly tested every morning, Cosby said. Staff will disinfect the area if they see diapers being changed near the water.

People are encouraged to shower before swimming, he said, “but policing that is something we haven’t undertaken. It’s almost impossible to do. Many people are there just to sunbathe or to take their kids.”

There is a stealth method for keeping pool water clean, Cosby said: Adult swim. Taking the kids out of the pool gives them time for a potty break.