The Environmental Protection Agency has put forward a proposal that could significantly curtail the authority of Native American tribes and states in regulating water quality for federal projects, a move experts warn will undermine tribal sovereignty and hinder their ability to safeguard vital water resources. At the heart of the proposed changes is a revision to Section 401 of the Clean Water Act, a critical piece of legislation that grants states and tribes a voice in certifying whether federal projects comply with water quality standards. This provision has historically served as one of the few robust mechanisms available to tribes to enforce treaty rights and protect their communities from potential environmental harm.

For developers undertaking projects such as dams, mines, data centers, or pipelines, a crucial step in the permitting process involves obtaining certification from the relevant state or tribal government, confirming that the proposed activity will meet federal water quality standards. Under regulations established by the Biden administration in 2023, this review process, often referred to as "activity as a whole," allowed tribes and states to conduct comprehensive assessments. These holistic evaluations considered a broad spectrum of potential impacts, including the risks of accidental spills, threats to culturally significant sites, and broader ecological consequences for wildlife and aquatic ecosystems.

However, the newly proposed rule seeks to drastically narrow the scope of these reviews, limiting them to "discharge only." This would mean that both states and tribes could only scrutinize projects based on the amount of direct pollution they release, effectively sidelining broader environmental and cultural considerations that are essential for protecting the delicate balance of water bodies.

Beyond altering the scope of project reviews, the proposed rule also introduces significant changes to how tribes can gain the authority to regulate water quality under the "Treatment in a Similar Manner as a State" (TAS) program. The TAS program is a cornerstone for tribal environmental stewardship, empowering tribes to act as regulatory bodies and directly impose conditions to mitigate factors that could pollute waters within or adjacent to their territories. To date, only 84 tribal nations have achieved TAS status, granting them the ability to review federal projects impacting their lands.

The current framework, as outlined in Section 401 of the Clean Water Act, permits tribes that can demonstrate sufficient capacity and resources to conduct water quality reviews, thereby extending regulatory powers beyond those tribes with more extensive financial and staffing resources. The proposed revision would fundamentally alter this, restricting such evaluations to only TAS-approved tribes and introducing a separate, more stringent authorization program that could further limit tribal involvement.

"Treaty rights are one of the strongest mechanisms to enforce against the federal government, against the state, against third-party actors, and in litigation," explained Heather Tanana, a law professor at the University of Colorado. "It takes years, it takes money, it’s complicated to do, and so you want these other mechanisms." The proposed changes, by reducing the efficacy of Section 401 reviews, place greater reliance on the arduous and often resource-intensive process of enforcing treaty rights, which can be a formidable challenge for many tribal governments.

According to Tanana, a reversion to pre-2023 regulations would impose a significantly higher burden on tribes to demonstrate extensive capacity, often necessitating the establishment of dedicated water departments. "There’s such a wide variance in tribes of what resources are available to them," she noted. "Do they have other sources of revenue, right? How many staff do they have? Do they have their own environmental departments? Is it one person, or is it 10?" This disparity in resources means that stricter capacity requirements would disproportionately affect smaller or less resourced tribes, potentially excluding them from meaningful participation in environmental decision-making.

During the Biden administration, tribes actively advocated for a baseline rule that would ensure all tribes had some input in federal projects, even as they pursued TAS status. However, industry opposition during the public comment period and subsequent political shifts led to the withdrawal of this proposed baseline rule by the EPA in December.

Patrick Hunter, a senior attorney at the Southern Environmental Law Center, highlighted that the impact of existing regulations is often less prohibitive than critics suggest. He pointed out that out of approximately 7,500 projects submitted during the Biden administration, fewer than 1 percent were ultimately denied. The vast majority were approved, often with specific conditions attached, such as the implementation of mitigation measures or the installation of sediment traps to prevent water pollution during the construction phases of projects. Tanana affirmed that the outcomes of tribal reviews mirrored this trend, indicating a collaborative approach rather than an obstructionist one.

The EPA’s own 2025 report on tribal consultations underscored widespread opposition to the proposed changes. "The clear feedback from the tribes was, ‘Don’t change it,’" Tanana stated. "’You’re going to make it harder for us to exercise our sovereignty to protect our waters and protect our community.’" This unified sentiment from tribal nations underscores the deep concern that the proposed rule represents a step backward in environmental justice and tribal self-determination.

A 30-day public comment period on the proposed rule is currently underway, offering a window for further feedback and engagement. However, given the strong opposition from tribal communities and environmental advocates, the rule is widely expected to face significant legal challenges once it is finalized.

"Tribes have an obligation to care for the rivers and waterways that have sustained their communities since before the existence of the United States and are weighing every option to protect their way of life," said Gussie Lord, head of tribal partnerships at Earthjustice. This commitment reflects a deep, ancestral responsibility to protect the natural world, a responsibility that is intrinsically linked to the health and well-being of their people and their cultural heritage. The proposed EPA rule, therefore, is seen not just as a regulatory adjustment, but as a direct threat to this fundamental obligation and the very existence of their traditional lifeways. The outcome of this regulatory battle will have far-reaching implications for environmental protection, tribal sovereignty, and the future of water resources across the nation.