EPA will spend more than $20 million to support the monitoring, the majority of which will be devoted to assist small drinking water systems with conducting the monitoring. The data collected under the Unregulated Contaminant Monitoring Rule 3 (UCMR 3) will inform EPA about the frequency and levels at which these contaminants are found in drinking water systems across the United States and help determine whether additional protections are needed to ensure safe drinking water for Americans. State participation in the monitoring is voluntary. EPA will fund small drinking water system costs for laboratory analyses, shipping and quality control.
The list of contaminants to be studied includes total chromium and hexavalent chromium, also known as chromium-6. Addressing hexavalent chromium in drinking water is a priority for EPA Administrator Lisa P. Jackson. In January 2011, EPA issued guidance to all water systems on how to assess the prevalence of hexavalent chromium and in the March 2011 proposal for UCMR 3, EPA invited comments on whether the agency should include chromium in the final rule. Public comments received by EPA were strongly supportive of adding total chromium and hexavalent chromium for monitoring.
EPA selected the contaminants by first reviewing the agency’s contaminant candidate list, which highlights priority contaminants that need additional research to support future drinking water protections. The contaminants on the list are known or anticipated to occur in public water systems. However, they are not addressed by existing national drinking water standards. Additional contaminants of concern were selected based on current occurrence research and health-risk factors.
EPA has standards for 91 contaminants in drinking water, and the Safe Drinking Water Act requires that EPA identify up to 30 additional unregulated contaminants for monitoring every five years.