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  2. Safe Drinking Water on Tribal Lands

Tribal Governments Role in Safe Drinking Water in Indian Country

Tribal Primacy 

On this page:

  • Background
  • What are the advantages and responsibilities of primacy?
  • Some Eligibility Requirements for TAS
  • Some Additional Resources and Contact Information about Tribal Primacy

Background

Primacy is the process through which federally recognized Indian Tribes, like states, implement and enforce federal environmental 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 Public Water System Supervision (PWSS) program and enforce regulations within their jurisdiction. 

Since 1976, Congress has appropriated funds under the SDWA for grants to help Tribes and states carry out PWSS programs.    

When first enacted in 1974, the SDWA did not contain a provision to enable Tribes to seek and assume primacy. As a result, EPA Regions were generally responsible for primary enforcement authority of the PWSS program in Indian country. In 1986, the SDWA was amended to allow Tribes to seek and assume primacy. 

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. 

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 PWSS program and enforces SDWA regulations. 


What are the advantages and responsibilities of primacy?

Primacy for the PWSS program allows the Tribes to establish and enforce environmental regulations for public water systems within their jurisdiction. 

Tribes that assume primacy also take over many of the responsibilities otherwise managed by EPA. These include, but are not limited to: 

  • Adopting and implementing the NPDWRs; 

  • Enforcing and responding to regulations; 

  • Maintaining compliance data systems; 

  • Certifying laboratories; and 

  • Performing sanitary surveys. 


Eligibility Requirements for TAS

Under EPA’s regulations, Tribes would generally apply for TAS and Primacy together, not separately. In order to be determined eligible for TAS for purposes of primacy over the PWSS program, a Tribe must meet the following criteria: 

  • Be recognized by the Secretary of the Interior; 

  • Have a Tribal government carrying out substantial duties and powers; for example, a government responsible for the health, safety and welfare of the affected community; 

  • Demonstrate that the regulatory functions to be performed in the public water systems are within the Tribe’s jurisdiction; and 

  • Be capable of administering an effective PWSS program consistent with the SDWA and all applicable regulations. 


Additional Resources and Contact Information about Tribal Primacy

  • Tribal Primacy: An Overview – a pamphlet that outlines the steps a Tribe should take to obtain primacy for the PWSS program. It discusses important considerations regarding primacy and describes the responsibilities of a Tribe that has primacy. 

  • TAS For the Public Water System Supervision Program: Factsheet - a quick reference guide to the TAS requirements and application process. 

  • TAS For the Public Water System Supervision Program: Frequently Asked Questions. 

The TAS Regulation has more information on TAS eligibility requirements and application procedures. For more information on the process of obtaining TAS for the Public Water System Supervision (PWSS) Program, contact your Regional Tribal Drinking Water Direct Implementation Coordinator. 

Safe Drinking Water on Tribal Lands

  • SDWA on Tribal Lands
  • Compliance with SDWA
  • Tribal Drinking Water Funding Programs
Contact Us About Safe Drinking Water on Tribal Lands
Contact Us About Safe Drinking Water on Tribal Lands to ask a question, provide feedback, or report a problem.
Last updated on May 13, 2026
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