An official website of the United States government.

Due to a lapse in appropriations, EPA websites will not be regularly updated. In the event of an environmental emergency imminently threatening the safety of human life or where necessary to protect certain property, the EPA website will be updated with appropriate information. Please note that all information on the EPA website may not be up to date, and transactions and inquiries submitted to the EPA website may not be processed or responded to until appropriations are enacted.

We've made some changes to EPA.gov. If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Monitoring Unregulated Drinking Water Contaminants

List of Laboratories Approved by EPA for the Fourth Unregulated Contaminant Monitoring Rule (UCMR 4)

This document provides a list of laboratories that met the fourth Unregulated Contaminant Monitoring Rule (UCMR 4) laboratory approval program application and proficiency testing criteria for the methods indicated.

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