That pool might look crystal clear and inviting on a hot day but a new study might make you think twice about diving straight in.
The bacteria E. Coli, most commonly associated with fecal matter, was found in more than half of water samples taken at public swimming pools in the Atlanta area.
The Centers for Disease Control sampled water from 161 public pools, both indoor and outdoor and 58 percent of them showed the presence of E.Coli.
Researchers could not definitely connect the presence of the bacteria with human feces but they made a pretty strong case that it "signifies that swimmers introduced fecal material into pool water."
"We don’t know how it got in there. It either washed off somebody’s body or somebody had a bowel movement in the pool," Michele Hlavsa, head of the CDC's Healthy Swimming Program said.
"It is time to stop treating the swimming pool as a toilet," Hlavsa told NBC. "Nowhere else except for the pool is it acceptable to poop in public or pee in public. In other places if we did this in public, we'd be arrested."
The likely culprits aren't just babies or toddlers wearing those not-so-protective swim diapers that can let fecal matter leak into the water.
Grown ups who don't shower properly before getting into the pool can bring fecal matter with them into the water.
A regular bowel movements, or "formed fecal incident" as the CDC puts it, isn't nearly as much of a problem as diarrhea, which can carry germs into the water that chlorine can't kill.
For E.Coli, a well chlorinated pool can take care of that quickly. Pool who regularly maintain their chlorine and pH levels shouldn't be a cause for concern.
But the CDC still recommends not drinking the water.