U.S. Clean Water Act (CWA) "Waters of the United States" (WOTUS) Definition: The 2025 Narrowing Amendment Proposal and Full Application of the Sackett Ruling
Overview
The definition of "Waters of the United States" (WOTUS), which determines the scope of Clean Water Act (CWA) jurisdiction, was significantly limited by the U.S. Supreme Court's decision in Sackett v. EPA (May 2023), which excluded wetlands and ephemeral streams lacking a "continuous surface connection" from federal jurisdiction. EPA under the Biden administration issued a conforming amendment in September 2023, but in November 2025, EPA and the U.S. Army Corps of Engineers (USACE) under the Trump administration published a new proposed WOTUS amendment rule that reflects the intent of the Sackett ruling to the fullest extent, further narrowing and clarifying federal jurisdictional waters. This proposal substantially narrows the area subject to federal CWA Section 404 (fill permit) and other requirements.
Enforcement Timeline
May 25, 2023: The U.S. Supreme Court issues the Sackett v. EPA decision, substantially limiting the scope of WOTUS jurisdiction
September 8, 2023: EPA/USACE under the Biden administration publish an interim federal rule responding to the Supreme Court decision
November 2025: EPA/USACE under the Trump administration publish a new WOTUS NPRM (proposed rule amendment) further clarifying and narrowing the scope of jurisdiction
As of 2026: While the rulemaking process for the new WOTUS rule proceeds, a dual structure with state-level water protection regulations has become established
Business Impact
Companies engaged in plant construction, land development, mining, or infrastructure projects in the United States are likely to find that obtaining federal CWA fill permits (Section 404 Permits) for wetlands or streams within a proposed development site becomes unnecessary or simplified, reducing development schedules and permitting costs. On the other hand, a divergence is emerging as states (such as Texas and California) move to require their own permits under state water protection law for wetlands and waters excluded from federal jurisdiction, making advance investigation of state environmental regulations in the relevant project location essential.