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EPA Releases Fifth UCMR4 Data Summary

Today, (10/17), EPA posted the fifth set of analytical results and a Data Summary for the Fourth Unregulated Contaminant Monitoring Rule (UCMR 4). Under the rule, all large public water systems (PWSs) and a representative subset of small PWSs are required to monitor for up to 30 contaminants (metals, cyanotoxins, pesticides, brominated disinfection byproducts, alcohols, and semi-volatile organic chemicals) between 2018 and 2020. The subject document includes a national summary of the data received as of 10/2/19. EPA will continue to update the information on UCMR’s occurrence webpage approximately quarterly. The data are subject to change until a final dataset is published in early 2022.

Manganese has been one of the more interesting UCMR4 contaminants due to its health advisory. This latest Data Summary shows that 58 PWSs have concentrations above the health advisory.