As of Aug. 13, nearly 162,000 people had alighted on 19 outdoor public pools managed by the city’s Department of Parks and Recreation. That’s a lot of cannonballs, a lot of lifeguard warnings, and a lot of competition for chaise longues.
It’s also a lot of feces.
Most people have about 0.14 grams of feces on their bottoms that, when rinsed off, can contaminate recreational water, according to the Centers for Disease Control and Prevention. That accumulation presumably derives from sloppy wiping habits, and if it’s to be trusted, D.C. pools have potentially hosted as much as 23,000 grams—or 50 pounds—of feces this summer. And that doesn’t even count the contributions from infants wearing porous swim diapers.
Even without the CDC’s precision on trace butt feces, we all know that John Q. Public is a dirty guy. Just look at most public restrooms: Without constant janitorial intervention, they’re sties.
And thus the challenge facing the staff at D.C.’s public pools. The facilities are open every day, their turnstiles stampeded by a population of overheated urbanites generally oblivious to their 0.14 grams of underside contamination. Many—actually, most—of them ignore the signs imploring them to take a shower before jumping in.
How could the pools possibly come clean in the face of this bacteriological onslaught?
With a lot of chemicals. According to the Department of Parks and Recreation (DPR), staffers at city pools check the water hourly. The Department of Health had conducted 70 pool inspections through July; it shut down no public facilities and five private ones (the names could not be determined by press time). “In all of the inspection reports that DPR has received from the Department of Health all levels of chlorine have been at expected levels to protect the public,” says DPR spokesperson John Stokes. “We understand the importance of protecting the public and have worked together with the Department of Health to reduce the risk of waterborne diseases.” For DPR staff, monitoring bacteria is every bit as important as scanning the water for sinking swimmers. Left untreated, the pool water can cause diarrhea, eye infections, skin rashes, and other infections that can even lead to death. That’s right; people have died from waterborne diseases caught at swimming pools. It hasn’t happened in the District in recent memory but the CDC says a few people die and there are thousands of non-fatal instances of Cryptosporidium, Giardia, Shigella, norovirus, and E. coli infection.
Though DPR’s swimming facilities have plenty of signage apprising bathers of the pool’s rules and regulations, there’s no sign to update patrons on the germ count. Meaning that every time you take a dip, you’re putting your health squarely in the hands of DPR and its corps of very young lifeguards.
Is that a smart gamble? Over two weeks in midsummer, Washington City Paper conducted bacteria tests at 24 city-run pools and three private pools in the District. Measurements were taken using Watersafe Bacteria Test kits made by Silver Lake Research, a Monrovia, Calif.–based laboratory that sells the tests primarily to public pool, spa, and water park managers.
The test kit is designed to scan the water for pseudomonas, E.coli, species of Aeromonas, Shigella, Enterobacter, Klebsiella—but not viruses and parasites that can also cause sickness.
Here’s how the test works: You dip the plastic dropper into the shallow end of the pool and squeeze a dropful of water into a plastic vial. Gently swirl the vial and watch the red-colored chemicals dissolve. Let it stand for seven minutes; swirl again. Place a test strip into the vial. Wait 10 more minutes. If only one line appears on the strip, the pool tested negative. But if two lines appear, the test is positive for bacteria.
The second line might be faint or dark. But even a faint one means a whole lot of colony-forming units of bacteria were found in the pool water sample.
“Nobody can tell you at what level you’ll get sick or get a rash. The real value of this test is it’s telling you at least 1,000 colony-forming units of bacteria are present,” says Tom Round, Silver Lake’s vice president of business development.
Considering that the Environmental Protection Agency defines drinking water as contaminated if it contains a single colony-forming unit of fecal coliform bacteria such as E.coli, the presence of 1,000 units is reason for caution, Round says.
“When you get a positive result it means it’s important to stay out of the water” until the pool can be disinfected, Round says. A negative result, meanwhile, doesn’t necessarily mean no harmful bacteria are in the pool, he added. It just means they haven’t reached a level detectable by the company’s 17-minute test.
The efficacy of the kit is by no means a matter of consensus in the pool-water-purity community. Some experts say the kit could yield false positives and cautioned that it’s not nearly as accurate as a professional lab analysis; others had the opposite concern—that the kits may underestimate the bacterial threat. “They are a bit of a black box. It’s not clear to us how sensitive these tests are,” says Michele Hlavsa, an epidemiologist in the CDC’s Division of Parasitic Diseases. “I would fear they couldn’t pick up enough of the bacteria and would give a false negative.” Whatever the accuracy of the on-site tests, a pool that comes up positive for bacteria one day can be clean the next, if it is properly treated.