EPA's Role in Safe Drinking Water on Tribal Lands

EPA works with Tribal governments and Tribal utilities to help their systems comply with the Safe Drinking Water Act (SDWA) to improve access to safe drinking water. EPA Regional offices generally serve as the primacy agency in Indian Country where a Tribe lacks primacy. As the primacy agency, EPA directly implements the Public Water System Supervision (PWSS) program and enforces SDWA regulations. Under the Safe Drinking Water Act (SDWA), EPA can approve “Treatment in the Same Manner as a State (TAS)” eligibility and authorize primacy for Tribes meeting certain requirements. These Tribes implement programs like the  PWSS program and enforce regulations within their jurisdiction. 

To receive primacy for the PWSS program, a Tribe must apply for and receive TAS status. Currently, the Navajo Nation is the only Tribe with TAS status and primacy over the PWSS program. Having primacy, the Navajo Nation enforces SDWA regulations and program requirements for public water systems within the boundaries of the Tribe’s approved program. For more information, please see the Tribal Primacy webpage.