Revisions to the Unregulated Contaminant Monitoring Rule (UCMR 4) for Public Water Systems and Announcement of Public Meeting

The U.S. Environmental Protection Agency (EPA) is finalizing a Safe Drinking Water Act (SDWA) rule that requires public water systems to collect occurrence data for contaminants that may be present in drinking water but are not yet subject to EPA's drinking water standards set under the SDWA. This rule identifies eleven analytical methods to support water system monitoring for a total of 30 chemical contaminants, consisting of nine cyanotoxins and one cyanotoxin group; two metals; eight pesticides plus one pesticide manufacturing byproduct (hereinafter collectively referred to as ``pesticides''); three brominated haloacetic acid disinfection byproduct groups; three alcohols; and three semivolatile organic chemicals. EPA is also announcing a public meeting and webinar to discuss the implementation of the fourth Unregulated Contaminant Monitoring Rule.