The Trump administration on Friday advanced a new regulatory step that would further limit which waterways fall under federal Clean Water Act protections, a move with outsized consequences for the arid West.
The Environmental Protection Agency and the Army Corps of Engineers jointly issued a supplemental proposed rule that, if finalized, would shrink the universe of streams and wetlands subject to Clean Water Act jurisdiction. The change would likely mean that development or pollution in these waters would no longer require federal permits or mitigation measures.
This latest proposal builds on an earlier rulemaking from the same agencies that already sought to narrow the law's reach. Together, they could significantly reduce federal oversight of water bodies across the country, particularly in western states where intermittent streams and seasonal wetlands are common.
EPA Administrator Lee Zeldin defended the move in a statement, saying the agency is working toward a “durable” rule that “follows the law and ends burdensome regulatory uncertainty.” He added that the supplemental notice reflects the agency's commitment to transparency and public input, and that feedback will help “strengthen the real-world expertise behind the final rule.”
The core question is which waters qualify as “Waters of the United States” and thus receive Clean Water Act protections. In 2023, the Supreme Court narrowed that definition to only waters that are “relatively permanent, standing or continuously flowing,” and required wetlands to have a “continuous surface connection” with a protected water body. But the court left room for interpretation, and the new proposal seeks to fill that gap.
Specifically, the EPA and Army Corps propose to define “relatively permanent” streams as those that hold water every day for at least 11 months of the year. Wetlands would only be protected if they have standing or flowing surface water that is continuously connected to a downstream regulated water for the same 11-month period.
Environmental advocates have warned that such strict definitions would exclude many seasonal waterways that are vital to western ecosystems and drinking water supplies. Industry groups, however, have long pushed for clearer and more limited federal jurisdiction, arguing that broad interpretations create costly permitting delays.
The proposal is now open for public comment, and the administration has signaled it intends to finalize a rule that would remain in place for years. The move comes as the administration has also faced legal challenges over its environmental rollbacks, including a recent court ruling that blocked an EPA bid to let Congress override California's clean air standards. That case underscores the ongoing judicial scrutiny of the administration's deregulatory agenda.
If adopted, the new rule would mark a significant shift in federal water policy, with potential implications for agriculture, development, and conservation across the western United States.
