Stage 2 Disinfection By-Products Rule

Disinfection By-Products (DBPs) form when disinfectants, such as chlorine, are added to drinking water and react with naturally occurring organic matter. These by-products can have adverse health effects, including cancer. DBPs in drinking water are regulated by the Stage 2 Disinfection By-Product Rule, which applies to all community water systems and non-transient non-community water systems by limiting the exposure to DBPs, specifically Total Trihalomethanes (TTHM) and Total Haloacetic Acids (HAA5). Other drinking water contaminants monitored through the Stage 2 Rule include chlorite, bromate, chlorine/chloramines, and chlorine dioxide disinfectants.

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