Under the Safe Drinking Water Act (SDWA), as amended in 1996, the Environmental Protection Agency (EPA) is required to establish criteria for a program to monitor unregulated contaminants and to publish a list of contaminants to be monitored. In response to this requirement, EPA published the revisions to the Unregulated Contaminant Monitoring Regulation (UCMR) for public water systems (PWSs) on September 17, 1999 (64 FR 50556), and in supplemental rules, including the Perchlorate and Acetochlor Rule (March 2, 2000 - 65 FR 11372), and the List 2 Rule (January 11, 2001 - 66 FR 2273). EPA expects to publish other rules detailing minor modifications to the UCMR program and List 3 monitoring requirements and analytical methods, as needed. This document was designed to provide an overview of the revised UCMR. It is intended to integrate the most essential elements of the UCMR, and to provide a reference guide to the UCMR guidance documents and UCMR rules published by EPA. This document briefly describes the three-tiered monitoring approach to the UCMR, monitoring schedules, reporting requirements, and the roles and responsibilities of States, EPA Regions, and PWSs in UCMR implementation. Note that this document does not explain all UCMR Program requirements in detail. Where more detailed and comprehensive information is available through other EPA guidance documents, the reader is referred to these documents.

"October 2001."