An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Monitoring Unregulated Drinking Water Contaminants

Monitoring for List 1 Contaminants by Large Public Water Systems from the First Unregulated Contaminant Monitoring Regulation Rule (UCMR 1)

This document contains the assessment monitoring requirements for List 1 contaminants by large public water systems from the first Unregulated Contaminant Monitoring Regulation Rule (UCMR 1).

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.

Assessment monitoring requirements for UCMR 1 (PDF)(3 pp, 25 K, January 2001, EPA 815-F-01-003)