1 of 6

Clean Water Act Tribal Provision

Discussion Paper Prepared by the U.S. Environmental Protection Agency

Office of Water and Office of General Counsel

May 2015

Purpose: This paper discusses a potential action that EPA is considering to revise its approach 

to tribal regulatory authority under the Clean Water Act (CWA or Act). From April to 

September 2014, EPA engaged in several discussions with tribes, states, and tribal and state 

organizations. During that time, we presented the basic concepts of the potential action, which 

had also been generally described in a 2011 EPA document titled Plan EJ 2014: Legal Tools. 

The pertinent part of that document and other information about EPA’s potential action are 

available at http://water.epa.gov/scitech/swguidance/standards/wqslibrary/tribal.cfm. 

Background: Congress enacted the CWA tribal provision (Section 518) as part of amendments 

to the statute in 1987. Among other things, Section 518 authorized EPA to treat eligible Indian 

tribes in a similar manner as states (a process that we refer to as TAS) for a variety of purposes, 

including administering each of the principal CWA regulatory programs and receiving grants 

under several CWA funding authorities. Section 518(e) establishes the eligibility criteria for 

TAS, including requirements that the tribe have a governing body carrying out substantial 

governmental duties and powers; that the functions to be exercised by the tribe pertain to the 

management and protection of water resources within the borders of an Indian reservation; and

that the tribe be reasonably expected to be capable of carrying out the functions to be exercised 

in a manner consistent with the terms and purposes of the Act and applicable regulations. For 

ease of reference, relevant language from Section 518(e)(2) and (h)(1) (which defines Indian 

reservations for purposes of the CWA) is excerpted below.

...the functions to be exercised by the Indian tribe pertain to the management and protection 

of water resources which are held by an Indian tribe, held by the United States in trust for 

Indians, held by a member of an Indian tribe if such property interest is subject to a trust 

restriction on alienation, or otherwise within the borders of an Indian reservation... (Section 

518(e)(2))

...‘Federal Indian reservation’ means all land within the limits of any Indian reservation

under the jurisdiction of the United States Government, notwithstanding the issuance of any 

patent, and including rights-of-way running through the reservation... (Section 518(h)(1))

In the early 1990’s, EPA promulgated regulations establishing TAS application and 

review procedures for a range of CWA regulatory programs available to tribes. Section 518 

makes no reference to any demonstration of regulatory authority to obtain TAS; rather, it 

requires only that the functions to be exercised by the applicant tribe pertain to the management 

and protection of reservation water resources. EPA nonetheless took a cautious approach by 

requiring that tribes seeking TAS for the purpose of administering a regulatory program under 

the Act must demonstrate their inherent jurisdiction to do so under principles of federal Indian 

law, including a demonstration of inherent authority over the activities of non-members of the 
2 of 6

tribe on non-member-owned fee lands.1EPA recognized at the time that there was significant 

support for the proposition that Congress had intended to delegate authority to otherwise eligible 

tribes to regulate their entire reservations under the Act. Notably, in a plurality opinion of the 

U.S. Supreme Court, Justice White had even cited Section 518 as representing a congressional 

delegation of authority to Indian tribes.2EPA also stated the Agency’s interpretation that in 

Section 518, Congress had expressed a preference for tribal regulation of surface water quality 

on reservations to assure compliance with the goals of the CWA. Nonetheless, in an abundance 

of caution, EPA opted at the time to require tribes to demonstrate, on a case-by-case basis, their 

inherent jurisdiction to regulate under the CWA. EPA was clear, however, that this approach 

was subject to change in light of further judicial or congressional guidance.3

Subsequent Developments: Since the promulgation of EPA’s CWA TAS rules in the 1990’s, 

there have been significant developments warranting reconsideration of EPA’s initial cautious 

approach to tribal jurisdiction. At this point, EPA has approved TAS applications from 49 tribes 

for the purpose of administering CWA regulatory programs – all of which have been for CWA 

Section 303(c) water quality standards (WQS) and Section 401 certifications. There have been 

three judicial challenges to these actions, and in all cases EPA’s determinations that the applicant 

tribes had demonstrated requisite jurisdiction and met the TAS requirements were upheld.4 

Importantly, the first court to review a challenge to an EPA CWA TAS approval readily agreed 

with an argument proffered by the applicant tribe – participating as amicus – that Section 518 is 

properly interpreted as an express congressional delegation of authority to Indian tribes over 

their entire reservations. Montana v. EPA, 941 F. Supp. 945, 951-52 (D. Mont. 1996), aff’d, 137 

F.3d 1135 (9th Cir.), cert. denied, 525 U.S. 921 (1998). The court also noted that a congressional 

delegation of authority to tribes “comports with common sense” to avoid a result where an 

interspersed mixing of tribal and state WQS could apply on a reservation depending on whether 

the waters traverse or bound tribal or non-Indian reservation land. Id. 

Additional judicial guidance arrived several years later during a challenge to EPA’s TAS 

regulation under a separate statute, the Clean Air Act (CAA). Arizona Public Service Co. v. 

EPA, 211 F.3d 1280 (D.C. Cir. 2000), cert. denied, 532 U.S. 970 (2001). EPA promulgated the 

CAA TAS rule in 1998 and in that context interpreted the CAA as including an express

congressional delegation of authority to eligible Indian tribes to regulate their entire reservations 

under that statute. 63 Fed. Reg. 7254 (February 12, 1998). As part of its analysis upholding 

EPA’s interpretation, the D.C. Circuit acknowledged similarities between the CAA and CWA 

 

1 Under principles of federal Indian law, demonstrations of inherent tribal authority over such non-member activities 

are guided by the principles expressed in Montana v. United States, 450 U.S. 544 (1981), and its progeny.

2 Brendale v. Confederated Tribes and Bands of the Yakima Nation, 492 U.S. 408, 428 (1989).

3 A useful description of EPA’s initial approach to tribal regulatory authority under the CWA can be found in the 

preamble to EPA’s TAS regulations for the Section 303(c) water quality standards program. 56 Fed. Reg. 64876 

(December 12, 1991).

4 Wisconsin v. EPA, 266 F.3d 741 (7th Cir. 2001), cert. denied, 535 U.S. 1121 (2002) (Sokaogon Chippewa 

Community); Montana v. EPA, 137 F.3d 1135 (9th Cir.), cert. denied, 525 U.S. 921 (1998) (Confederated Salish and 

Kootenai Tribes of the Flathead Reservation); Montana v. EPA, 141 F.Supp.2d 1259 (D. Mont. 1998) (Assiniboine 

and Sioux Tribes of the Fort Peck Reservation).
3 of 6

TAS provisions, as well as EPA’s different approach under the CWA. 211 F.3d at 1291-92. The 

court noted with significance that EPA’s approach under the CWA had not been subjected to 

judicial review and observed favorably the district court’s statements in Montana v. EPA that 

Section 518 plainly indicates congressional intent to delegate authority to Indian tribes. Id.

Ultimately, the D.C. Circuit recognized that EPA had taken a cautious approach under the CWA 

but that there was no reason to do so again under the CAA. Id.

A dissenting judge in the CAA case predicated his disagreement with the majority largely 

on the absence from the CAA of language expressly describing the reservation areas over which 

tribes would exercise jurisdiction as including all reservation lands notwithstanding the issuance 

of any patent and including rights-of-way running through the reservation. Id. at 1301-05. The 

dissent viewed this language as critical to an expression of congressional intent that tribes are to 

exercise delegated authority over all reservation lands, including lands owned by non-members 

of the tribes. Id. Notably, the dissent observed that the key “notwithstanding” language is, in 

fact, included in the relevant tribal provisions of the CWA. Id. at 1302 (also referencing 

Brendale, 492 U.S. at 428). The dissent noted that in spite of the statement in Brendale, EPA 

had determined not to treat CWA Section 518 as a congressional delegation; however, the 

dissent also observed that no court had yet resolved the issue. Id.

Although no court has decided the issue of whether CWA Section 518 constitutes an 

express delegation of authority to tribes, EPA believes it is of great import that the three courts 

that have considered the issue have favorably viewed such an interpretation: the U.S. Supreme 

Court in Brendale, the federal district court in Montana v. EPA, and the D.C. Circuit in APS. 

EPA also believes that the CAA TAS provision – enacted only three years after CWA Section 

518 – provides useful guidance regarding Congress’ understanding of the importance of uniform 

tribal regulation of mobile environmental pollutants within reservations, and that this

understanding can fairly be traced back to the 1987 enactment of CWA Section 518. In light of 

this clear direction, EPA believes it is appropriate to revisit our interpretation of tribal regulatory 

authority under the CWA. Revising our interpretation and concluding definitively that Section 

518 constitutes a congressional delegation of authority would eliminate unnecessary 

administrative burdens not set forth in the statute, would provide greater consistency in the 

processing of TAS applications across EPA statutes with similar tribal provisions, and would 

thus ultimately provide greater fairness to applicant Indian tribes. 

Potential Change: If EPA proceeds with the new approach, a tribe applying for TAS to 

administer CWA regulatory programs would be able to rely on a congressional delegation under 

Section 518 as the source of its authority to regulate reservation waters, including the waterpolluting activities of non-tribal members on their reservation lands. Tribes would no longer 

need to make a separate showing of inherent authority. All other aspects of the TAS criteria and 

regulatory procedures would remain unchanged.
4 of 6

Questions and Answers

During the 2014 outreach discussions, EPA received questions that helped clarify some 

of the issues that may be raised as we consider revising our interpretation of Section 518. We 

provide our initial views on some of those issues below.

1. Would the potential revised interpretation affect the processing of eligible tribes’

CWA regulatory programs?

No. Tribes that receive TAS would remain subject to all existing requirements applicable 

to submission and review of their actual regulatory programs. EPA’s review of a tribe’s program 

submission – e.g., a tribe’s submission of water quality standards under Section 303(c) –

involves a separate action from the approval of TAS eligibility. The potential revised 

interpretation would not approve any tribe’s actual regulatory program; nor would it alter any

applicable programmatic requirements.

2. Would the potential revised interpretation alter the geographic scope of TAS?

No. The potential revised interpretation would not affect – either by expanding or 

contracting – the geographic scope of tribal TAS eligibility under the CWA. Under Section 518, 

tribes can only obtain TAS status over their reservations. Tribes can seek TAS with respect to 

water resources pertaining to any type of on-reservation land, including, for example, reservation 

land held in trust by the United States for a tribe, reservation land owned by or held in trust for a 

member of the tribe, and reservation land owned by non-tribal members.5 But tribes cannot 

obtain TAS under the CWA for water resources pertaining to any non-reservation land.6This 

basic limitation would be unaffected by the potential revised interpretation. In addition, EPA’s 

existing CWA TAS regulations provide for applicant tribes to submit a map or legal description 

of the reservation area that is the subject of the TAS application. See, e.g., 40 C.F.R.

131.8(b)(3)(i). This provision would continue to apply and would ensure that each tribe applying 

for a CWA regulatory program submits information adequate to demonstrate the location and 

boundaries of the subject reservation.

3. Would the potential revised interpretation affect tribal criminal enforcement 

authority?

No. The potential revised interpretation would not affect any existing limitations on 

tribal criminal enforcement authority. The interpretive change EPA is considering relates solely 

 

5

For purposes of EPA’s programs, Indian reservations include both formal reservations and informal reservations 

(i.e., trust lands validly set aside for Indian tribes that have not been formally designated as an Indian reservation). 

See, e.g., 56 Fed. Reg. at 64881.

6 Many tribes have rights to hunt, fish, gather resources, or perform other activities in areas outside of their 

reservations. To the extent the lands on which these rights are exercised are not Indian reservation lands as defined 

at 18 U.S.C. 1151(a), tribes cannot obtain TAS under the CWA for water resources pertaining to such lands.
5 of 6

to Indian tribes’ civil regulatory authority to administer CWA programs on their reservations; it 

would not address or in any way alter the scope of tribal criminal enforcement jurisdiction.

4. Would interested entities still be able to comment on a tribe’s assertion of 

jurisdiction?

Yes. EPA’s existing CWA TAS regulations provide opportunities for potentially 

interested entities to provide input to EPA regarding any jurisdictional issues associated with a 

tribe’s TAS application. For instance, EPA’s TAS regulations for the CWA Section 303(c) 

WQS program include a process for notice to appropriate governmental entities – states, tribes 

and other federal entities located contiguous to the reservation of the applicant tribe – and 

provide an opportunity for such entities to comment on the applicant tribe’s assertion of 

authority. EPA also routinely makes such notices broad enough – e.g., through publication in 

local newspapers and electronic media – that other potentially interested entities can participate 

in the process. These procedures would continue to apply in full. Under the potential revised 

interpretation of Section 518, the principal jurisdictional issue would likely be the boundaries of 

the subject reservation.7 However, to the extent a particular application presents a separate 

jurisdictional issue, the existing notice-and-comment procedures would be available to raise such 

an issue to EPA for due consideration.

5. What about special circumstances unique to specific tribes?

EPA is aware that there could be unusual circumstances that limit or preclude a particular 

tribe’s ability to accept or effectuate a congressional delegation of authority over its reservation. 

For example, there could be a separate federal statute establishing unique jurisdictional 

arrangements for a specific state or a specific reservation that could affect a tribe’s ability to 

exercise authority under the CWA. It is also possible that provisions in particular treaties or 

tribal constitutions could limit a tribe’s ability to exercise relevant authority. Existing CWA 

TAS regulations require applicant tribes to submit legal statements describing the basis for their 

assertions of authority and provide opportunities for potentially interested entities to comment on 

the assertion of authority. These requirements would continue to apply and would ensure that 

any special circumstances are addressed in a tribe’s TAS application and that interested entities 

will have an opportunity to raise such issues and provide their views.8

 

7 EPA notes that the geographic scope of a tribe’s TAS application – i.e., the boundary of the reservation area that a 

tribe seeks to regulate – is already a relevant jurisdictional issue under EPA’s current approach to tribal jurisdiction 

under the CWA. The potential revised interpretation would thus impose no additional burden on entities that wish to 

comment on an applicant tribe’s reservation boundary.

8 EPA is aware that Section 10211(b) of the Safe, Accountable, Flexible, Efficient Transportation Equity Act of 

2005 (SAFETEA), Public Law 109-59, 119 Stat. 1144 (August 10, 2005) established a unique TAS requirement 

with respect to Indian tribes located in the State of Oklahoma. Under Section 10211(b), tribes in Oklahoma seeking 

TAS under a statute administered by EPA for the purpose of administering an environmental regulatory program 

must, in addition to meeting applicable TAS requirements under the EPA statute, enter into a cooperative agreement 

with the State that is subject to EPA approval and that provides for the tribe and state to jointly plan and administer 

program requirements. This requirement exists apart from, and in addition to, existing TAS criteria, including the 

TAS criteria set forth in Section 518 of the CWA. The potential revised interpretation that EPA is considering 
6 of 6

6. Would there be effects on tribes that EPA has previously found eligible for TAS?

No. There would be no effect on tribes that EPA has previously found eligible for TAS

for the purpose of a CWA regulatory program.

7. Would the potential revised interpretation affect any EPA-approved state 

programs?

No. The potential revised interpretation would have no effect on the scope of existing 

state regulatory programs approved by EPA under the CWA. It would neither diminish, nor 

enlarge, the scope of such approved state programs.

8. How would tribes and states address differences in their respective regulatory

programs?

Regulations already exist to address circumstances where a state or tribe believes that

unreasonable consequences could arise or have arisen as a result of differing WQS set by states 

and eligible Indian tribes on common bodies of water. Section 518(e) of the CWA required EPA 

to provide a mechanism to address such situations. The Agency did so at 40 C.F.R. 131.7, which 

establishes a detailed dispute resolution mechanism. The potential revised interpretation would

not affect that process; it would remain available as needed to address potential state/tribal

issues.

9. Would the potential revised interpretation affect TAS applications for CWA grant 

funding?

The potential revised interpretation would not address or affect the TAS requirements or 

review process for tribes to receive grants. The receipt of grant funding does not involve any 

exercise of regulatory authority. Therefore, a determination of TAS eligibility solely for funding 

purposes does not, under existing regulations, require an analysis or determination regarding an 

applicant tribe’s regulatory authority.

10. If EPA decides to move forward, what process will it use?

If EPA decides to move forward with the revised interpretation, we would publish a 

notice proposing the revision in the Federal Register and provide an opportunity for comment 

prior to proceeding with any final interpretive change. There will thus be an additional 

opportunity for interested entities to provide their views to EPA at that point.

 

relates solely to the interpretation of an existing CWA TAS requirement; it would thus have no effect on the separate 

TAS requirement of Section 10211(b) of SAFETEA.