When you dive into the cool, crisp water at your local pool on a hot summer day, concern over microbes may not be the first thing that goes through your mind. But that chlorinated water may not be as clean as you would think -- because people may have peed in the pool.
In 2009, a survey by a group known as the Water Quality and Health Council found that 1 in 5 people urinate in the pool -- a problem that may have more implications for your health than the simple "ick factor."
The Water Quality and Health Council is sponsored by Chlorine Chemistry Division of the American Chemistry Council, an industry trade association. It's a group that would arguably want people to have the cleanliness of their pools in mind.
Still, simple chemistry supports the notion that urine can actually deplete the chlorine levels in pools. At the root of the problem is the interaction between the ammonia in urine and the chlorine in a pool, which forms a chemical called chloramine.
Aside from potentially giving off noxious fumes, chloramine, it turns out, is actually less effective at killing bacteria than chlorine, possibly leading to an increased risk of water-borne infections.
This might not be such a problem if people heeded the imperative commonly posted on signs at public pools shower before they get into the pool -- a step the U.S. Centers for Disease Control and Prevention calls "the first defense against germs that can make swimmers sick." But the Water Quality and Health study revealed that nearly 70 percent of people taking a dip in the pool do not shower beforehand.
The CDC reports that in 2008, poor water quality led to one out of every eight public pool closings. Those pool closings are for a good reason; past reports suggest many have fallen victim to infections from the pool.
One such victim is Brody Weiss, son of ex-Atlanta Braves Shortstop Walt Weiss. Brody contracted E. coli from a recreation park wading pool in 1998 when he was 3 years old. After Brody became ill, tests at the park revealed chlorine levels below the level needed to kill E. coli.
He nearly died.
"I lost 50 percent function of his kidneys before dialysis restored me to health," said Brody, now 17. "I look back on it a little bit and know I'm lucky to be here."
E. coli can be a nasty bug. Dr. Charles Patrick Davis, a San Antonio, Texas-based emergency medicine doctor, noted that symptoms of infection "may include a low fever, nausea, vomiting, stomach cramps and bloody diarrhea."
In this case, Brody wasn't the only one affected. Health officials in Georgia, where the recreation park is located, later determined that a child with E. coli had defecated in the wading pool at the park and that other children, too, swallowed the contaminated water. In total, seven other people contracted E. coli at the same water park close to the time as Brody, and one child died.
Unfortunately, it's not just E. coli. Health experts say that chloramine can also lead to wide varieties of bacterial infections including shigella, campylobacter, salmonella, hepatitis A and other forms of parasitic infections. In addition, chloramines -- not chlorine itself -- are often responsible for those stinging red eyes that we normally associate with a day at the pool.
The good news is that the CDC offers tips that you can follow to safeguard yourself and everyone around you when it comes to pool etiquette:
CDC's 6 Tips for Healthy Swimming
Don't swim when you have diarrhea.