EPA's Role in Safe Drinking Water in Indian Country

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.

Under the Tribal Public Water System Supervision (PWSS) program EPA collects drinking water compliance data. The data is analyzed to determine compliance with SWDA in Indian country. 

EPA stores this information in the Safe Drinking Water Information System (SDWIS). SDWIS contains information about public water systems and their violations of EPA's drinking water regulations. EPA gauges compliance with the National Primary Drinking Water Regulations through a metric that tracks the percentage of the CWSs that have met all applicable health-based drinking water standards in the preceding year. 

Health-based violation data for community water systems under EPA primacy and Navajo Nation primacy in Indian country are included in Table 1 (including health-based violations for active systems during any part of 2025). 

Table 1. Health-based violations for community water systems under EPA and Navajo Nation primacy in Indian country (Calendar Year 2025). 

EPA performs Sanitary Surveys to assess a PWS’s ability to provide safe drinking water to the community. A sanitary survey is an on-site review of a PWS’s source, facilities, equipment, operation and maintenance. Surveys identify sanitary deficiencies and technical needs and assess a system’s capacity and structural integrity. 

The following eight areas are evaluated for compliance: 

There is a federal mandate to perform sanitary surveys for all public drinking water systems. EPA performs the surveys on Tribal lands where EPA is the primacy agency. Most importantly, these surveys provide an opportunity for EPA to work with a system to lower the risk of contamination and waterborne disease. 

Source water assessments are another integral part of ensuring that a water system is providing safe drinking water to the community. These assessments are different for each system. They analyze existing and potential threats to the quality of the PWS and identify protection measures to address these them. 

EPA may perform an assessment or help establish Source Water Assessment Programs (SWAPs) for a Tribal PWS. 

EPA implements the Safe Drinking Water Act and program requirements on Tribal lands. EPA Regions help Tribal water systems meet these regulations and requirements so that they can deliver safe drinking water to their Tribal community. 

Several types of assistance that EPA provides for Tribal systems: 

Technical Assistance 

At Tribal utilities, EPA’s Public Water Systems Supervision (PWSS) program: 

EPA also helps to build the public water system’s capacity by providing technical assistance as part of the PWSS grant program. 

Water System Infrastructure Assistance 

EPA’s Drinking Water Infrastructure Grant – Tribal Set Aside (DWIG TSA) Program provides resources to assists Tribes in improving water system infrastructure. Community water systems and non-profit non-community water systems serving Tribal populations are eligible for project funding. 

WIIN Act Tribal Grants 

The 2016 Water Infrastructure Improvements for the Nation Act (WIIN Act) addresses, supports, and improves America's drinking water infrastructure.  Included in the WIIN Act were three new Tribal drinking water grants that promote public health and the protection of the environment in Tribal communities. The three grant programs include:  

The EPA collaborates extensively with other federal agencies to ensure effective and efficient implementation of its Tribal programs. An example of this is the Infrastructure Task Force (ITF). The primary focus of the ITF is to improve access to safe drinking water, basic sanitation and solid waste services in Indian country. 

The federal partners participating in the task force include: 

The agencies accomplish the goals of the ITF by coordinating federal efforts in delivering water infrastructure, wastewater infrastructure, and solid waste management services to Tribal communities. These lead to a streamlined approach to agency policies, regulations, and directives. Streamlining reduces the administrative burden for Tribal communities and facilitates access to funding.