EPA recently released new data compiled from the agency’s Fourth Unregulated Contaminant Monitoring Rule (UCMR 4). UCMR 4 required all large utilities and a representative sample of small utilities to test for a series of 30 chemical contaminants (nine cyanotoxins and one cyanotoxin group; two metals; nine pesticides; three brominated haloacetic acid [HAA] disinfection byproducts groups; three alcohols; and three semivolatile organic chemicals). The data will be continually updated over the course of the reporting cycle (2018-2020).
The data summary includes information on the total number of tested public water systems (PWSs) with results at or above the minimum reporting level, and the number and percentage of tested PWSs with results above the reference concentration.