With pool weather comes the warning, that even treated water doesn't guarantee waterborne illnesses are gone.
The Centers for Disease Control says 208 outbreaks were linked to treated recreational water venues from 2015 to 2019.
Those venues included pools, hot tubs and water playgrounds.
The outbreaks led to more than 3,600 cases of illnesses and 13 deaths.
Infections peaked in July.
The deaths were all connected to a Legionnaire's disease outbreak, which is waterborne.