By Piper Weiss, Shine Staff | Healthy Living

If you're taking a refreshing dip in a pool with four other people, odds are one of you is urinating. This is not gross-out myth, but cold, depressing fact from a recent survey conducted by the Water Quality & Health Council, a scientific research group sponsored by the American Chemistry Council.

The survey, conducted in April, asked nearly 1,000 adults whether they urinate in pools. One in five bravely admitted their mistakes. And those are the ones who admitted it.

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We may act like potty-trained adults on land, but something about a body of water, even a small one, opens our natural floodgates and, according to doctors, puts us all at risk.

"No matter how easy it is to pee anonymously in the pool, swimmers should avoid doing so," says public health expert and WQHC chairman, Dr. Chris Wiant.

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It is easy isn't it? Maybe that's because many of us were taught as kids that chlorine counteracted any accidents. Technically, that's mostly true. If pool operators maintain proper chlorine and pH levels, most waterborne germs are killed on contact.

But 54 percent of public pools tested by the WQHC last year failed to provide the proper chlorine levels and 47 got low marks for pH balance. You can blame poor pool maintenance, but frequent urinators don't help.

"Anything foreign that gets in the pool consumes disinfectant and makes the pool less capable of catching the next bug," Dr. Wiant tells Yahoo! Shine. So while chlorine is working overtime to clean up someone's mess, it's weakened by the time more serious bacteria dives in.

That comes from the germs we carry on our body even before we get into to the water. While only one in five of us cop to peeing in the pool, seven in 10 say they don't shower before they swim. As much as a cold pre-swim shower ruins that first dip feeling, Wiant makes a good case for why it's crucial.

(You may want to stop eating lunch right now, before reading on.)

The additional bacteria we carry on skin, in particular sweat and traces of fecal matter (yes even on adults),gets mixed in the pool. "If disinfectant isn't right, bacteria is allowed to grow in pools, so someone accidentally consumes a mouthful of water like we all do when we're swimming and suddenly they're subject to serious bacteria like E.coli or salmonella."

The high risk offenders, according to the Center for Disease Control, are those water recreational parks, a dangerous combination of packs of young swimmers and lots of accidental gulps. One targeted study by Georgia's Division of Public Health found that e.Coli infected at least 26 people at one water park in the summer of 1998, ultimately resulting in one fatality. Another study found the parasite Cryptosporidium survives even well-chlorinated water parks, posing a potentially fatal threat to those with lowered immune systems.

But small private pools and large public ones are also potential health hazards, depending on how they're maintained. The CDC notes a rapid rise in gastro-intestinal illnesses borne from dirty swimming pools across the country in the past two decades.

Short of getting pool maintenance certification or sweating out an unbearable summer, what can you do?

The first step is to be a good pool Samaritan. Take it to the restroom, folks, and emphasize lots of bathroom breaks for your kids. Another important to-do: always shower before getting in the pool. If you've done your part, you still can't trust your blissfully clueless fellow swimmers.

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To find out of your pool is safe, look for some tell-tale signs of bacteria.

"Check if you see the bottom," says Dr. Wiant. "If a pool is clear it's likely very clean and balanced, but if it's it cloudy or the sides are slimy, those are signs that bacteria is prevalent and the pool isn't filtering out germs the way it should."

Hyper-vigilant swimmers can also purchase pool test strips at any drug store and do their own scientific assessment. "They're easy to use," he adds, "just crack one open and dip it in the pool and you'll be able to tell right away if the pool is clean."

Another signal it's time to get out of the pool: burning, stinging eyes. Although it's not seriously harmful, when "urine combines with chlorine it becomes an irritant," Wiant says. So if you find yourself squinting in pain after a dive, ask yourself why that person doing the backstroke in the next lane looks so relaxed. It's not that nice of a day.