In a 26-page report, "The Natural Resources Defense Council" finds nearly one in four Americans drinking water comes from untested or contaminated systems.
Hillsborough County uses chloramine, a mixture of chlorine and ammonia, so does Manatee County.
Pinellas County uses chloramine, but twice a year they switch to just chlorine for 21 days because its a stronger disinfectant to kill off bacteria.
The county admits there are other options to disinfect, but this is the best and most cost effective way for them.
