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 This website is no longer updated and links to external websites and some internal pages may not work.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 »

Drinking Water Requirements for States and Public Water Systems

Memo Clarifying Requirements and State Reporting Guidance to Transition to the Revised Total Coliform Rule

This memorandum provides guidance to primacy agencies with enforcement responsibility under the Safe Drinking Water Act (SDWA) concerning the requirements to transition public water systems (PWSs) from the Total Coliform Rule (TCR) to the Revised Total Coliform Rule (RTCR). This transition started April 1, 2016 or on an earlier State effective date, whichever comes first.

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