Unregulated Contaminant Monitoring Rule (UCMR) Update: Completing UCMR 4 and Considerations for UCMR 5

Drinking Water
Oral Presentation

Presented by J. Toothman
Prepared by D. Hautman
USEPA, OGWDW, SRMD, TSC, 26 W. Martin Luther King Dr, Cincinnati, OH, 45268, United States

Contact Information: [email protected]; 513-569-7274


The 1996 amendments to the Safe Drinking Water Act (SDWA) require that the United States Environmental Protection Agency (EPA) establish criteria for a program to monitor unregulated contaminants and publish a list of up to 30 contaminants to be monitored every five years. On December 20, 2016, EPA published the fourth Unregulated Contaminant Monitoring Rule (UCMR 4), listing monitoring and reporting requirements for 30 chemical contaminants. The UCMR provides EPA and other interested parties with scientifically valid data on the occurrence of these contaminants in drinking water, the population potentially exposed and the levels of that exposure. These data are one of the primary sources of occurrence and exposure information the agency uses to develop regulatory decisions for these contaminants. The UCMR 4 monitoring period began January 2018 and continues until December 2020. EPA maintains direct regulatory implementation responsibilities for UCMR 4 with significant assistance from partnering states. This presentation provides an update on UCMR: past, present and future and reviews UCMR 4 implementation activities including electronic data and QC reporting, the laboratory approval and oversight program, PWS compliance assistance and successes/challenges with implementing this complex national program.