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Revised Interpretation of the Clean Water Act Tribal Provision

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Section 518 of the Clean Water Act (CWA) authorizes EPA to treat eligible Indian tribes with reservations in a similar manner to states (TAS) for a variety of purposes, including administering each of the principal CWA regulatory programs and receiving grants under several CWA authorities.

EPA’s revised interpretation of CWA section 518 published on May 16, 2016, streamlines the process for applying for TAS for CWA regulatory programs, including the water quality standards program. This reinterpretation facilitates tribal involvement in the protection of reservation water quality as intended by Congress.

Final Interpretive Rule

Since 1991, EPA has followed a cautious approach that requires applicant tribes to demonstrate inherent authority to regulate waters and activities on their reservations under principles of federal Indian common law.

The agency has consistently stated that its approach was subject to change in the event of further congressional or judicial guidance addressing tribal authority under section 518 of the Clean Water Act.

Based on such guidance, and after considering public comments, EPA concludes definitively that section 518 includes an express delegation of authority by Congress to Indian tribes to administer regulatory programs over their entire reservations, subject to the eligibility requirements in section 518.

This final interpretive rule will reduce burdens on applicants associated with the existing TAS process and has no significant cost.

Proposed Interpretive Rule

In August 2015, EPA proposed the interpretive rule, Revised Interpretation of Clean Water Act (CWA) Tribal Provision, and invited public comment. EPA proposed to streamline how tribes apply for TAS for the water quality standards program and other CWA regulatory program. Specifically, EPA proposed to conclude definitively that section 518 of the CWA includes an express delegation of authority by Congress to eligible Indian tribes to administer regulatory programs over their entire reservations.

EPA provided a 60-day public comment period after the proposed interpretive rule was published in the Federal Register on August 7, 2015.

Post-Proposal Outreach

EPA contacted tribal governments, states and state associations separately to provide opportunities for consultation and coordination.  EPA also hosted a webinar for the public on Thursday, September 10, 2015.

Pre-Proposal Outreach

Tribal Consultation and Coordination

In EPA's April 18, 2014 letter to tribal leaders, EPA initiated consultation and coordination with federally-recognized Indian tribes concerning the potential reinterpretation of Clean Water Act provisions regarding TAS. On May 22 and 28, 2014, EPA held two tribes-only consultation and coordination webinars. For more information, refer to the docket for this rulemaking.

Intergovernmental Consultation and Coordination

In EPA's June 18, 2014, letter to Intergovernmental Associations, EPA invited input from these organizations.  On July 8, 2014, EPA discussed a presentation titled "Potential Reinterpretation of a Clean Water Act Provision Regarding Tribal Eligibility to Administer Regulatory Programs" with these organizations. For more information, refer to the docket for this rulemaking.

Reference Materials


Treatment in the same manner as a State (TAS) Procedures for Clean Water Act Regulatory Programs

EPA Guidance

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