NATIONAL PRIMARY DRINKING WATER REGULATIONS - DISINFECTANTS AND DISINFECTION BYPRODUCTS

EPA has finalized maximum residual disinfectant level goals (MRDLGs) for chlorine, chloramines, and chlorine dioxide; maximum contaminant level goals (MCLGs) for four trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane, and bromoform), two haloacetic acids (dichloroacetic acid and trichloroacetic acid), bromate, and chlorite; and National Primary Drinking Water Regulations (NPDWRs) for three disinfectants (chlorine, chloramines, and chlorine dioxide), two groups of organic disinfection byproducts (total trihalomethanes (TTHMs) a sum of the four listed above plus monochloroacetic acid and mono -- and dibromoacetic acids), and two inorganic disinfection byproducts (chlorite and bromate). The NPDWRs consist of maximum residual disinfectant levels (MRDLs) or maximum contaminant levels (MCLs) or treatment techniques for these disinfectants and their byproducts. Regulations promulgated are known as the Stage 1 Disinfection Byproducts Rule (DBPR). The Agency believes the rule will provide public health protection for an additional 20 million households that were not previously covered. The Stage 1 DBPR applies to public water systems that are community water systems (CWSs) and nontransient noncommunity water systems (NTNCWs) that treat their water with a chemical disinfectant for either primary or residual treatment. In addition, certain requirements for chlorine dioxide apply to transient noncommunity water systems (TNCWs).

(Federal Register, 12/16/98)