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Implementation and Reevaluation of Existing Regulations
The Safe Drinking Water Act requires EPA to set standards for 83 specific contaminants, to review each of them at least once every six years, and to revise them if appropriate. Decisions about revisions are based primarily upon improved scientific understanding of risks resulting from more advanced knowledge of potential exposures, hazards posed by the agents, or interpretation of exposure and hazard information. Because of Office of Water priorities for risk reduction, and scientific opportunities for improving certainty of risk estimates, the NERL drinking water Existing Regulations Research program is focused on improving EPA's ability to assess and interpret exposures to agents regulated by the Arsenic Rule, the Ground Water / Surface Water Treatment Rules, and the Disinfection By-Product (DBP) Rules.