In a final interpretative rule, the EPA has streamlined the process whereby federally recognized tribes with reservations apply to the Agency to be treated in a manner similar to states (TAS) for the purposes of administering Clean Water Act (CWA) regulatory programs. The primary change under the interpretative rule is that tribes will no longer be required to demonstrate their inherent authority to regulate under the CWA. According to the EPA, the interpretive rule is derived from CWA Section 518, which includes Congress’s express delegation of authority to Indian tribes to administer regulatory programs over their entire reservations, subject to the eligibility requirements in Section 518.
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The EPA notes that since 1991, it has followed a “cautious interpretation” of the CWA tribal provision, which has required tribes, as a condition of receiving TAS regulatory authority under Section 518, to demonstrate inherent authority to regulate waters and activities on their reservations under principles of federal Indian common law. The EPA derived the inherent authority test from a U.S. Supreme Court decision (Montana v. United States, 1981). Under the test, tribes need to show that there are waters within the subject reservation used by the tribe or its members; that the waters are subject to protection under the CWA; and that impairment of the waters by nonmember activities on fee lands would have serious and substantial effects on tribal health and welfare.