Why are public water supplies disinfected?
Water drawn from surface water sources (lakes or ponds) must be disinfected to kill bacteria, viruses and other organisms that can cause serious illness and death. Primary disinfection at the treatment plant is required by law under the EPA Surface Water Treatment Rule. In Vermont all systems use chlorine primary disinfection. A secondary disinfectant (chlorine, monochloramine or chlorine dioxide) is also required to treat any type of contamination that could occur after the water leaves the treatment plant. Due to drinking water disinfection, there are no outbreaks of cholera, typhus, or other waterborne diseases that kill over 10 million people each year in places where drinking water supplies are not disinfected.
