The CDC has warned the public about a recent rise of several gastrointestinal illnesses that have been linked to swimming in pools.
The bug is caused by a microbe that is resistant to chlorine and comes from sick people who swim in the pool when they have the stomach bug. It then spreads by infecting other swimmers who swallow pool water.
Health officials say to not swallow the pool water and to avoid the pool if you are sick.
On another note, researchers say they found an average of 20 gallons of water in pools that are one-third the size of Olympic-size pools.