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The Safe Drinking Water Act (SDWA), as amended in 1996, requires EPA to establish criteria for a program for public water systems (PWSs) to monitor for not more than 30 unregulated contaminants every five years. The Unregulated Contaminant Monitoring Regulation supporting the second cycle (UCMR 2) of monitoring was signed on December 20, 2006. The UCMR 2 requires monitoring for 25 contaminants using five analytical methods. EPA, the states, laboratories and PWSs are preparing for monitoring to occur during 2008-2010.

Federal Register Notice: Revisions to the Unregulated Contaminant Monitoring Regulation (UCMR) for Public Water Systems

UCMR 2 Compared to UCMR 1

UCMR 2 builds on the established structure of UCMR 1, and makes some changes to the rule design that are intended to streamline and improve the regulation. As will be true for every UCMR cycle, a new list of contaminants and analytical methods are defined. In addition, UCMR 2 includes the following primary changes reflecting “lessons learned” from UCMR 1:

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