In our February 2026 article, WOTUS 2025/2026: The Regulatory Pendulum Swings Again as Agencies Propose New Definitions, we described the Environmental Protection Agency’s (“EPA”) and U.S. Army Corps of Engineers’ (“USACE”) (together, the “Agencies”) November 20, 2025 proposal.
The proposal would codify, for the first time in regulatory text, the twin pillars of the Supreme Court’s Sackett v. Environmental Protection Agency (“Sackett”), 598 U.S. 651 (2023), decision for what qualifies as “waters of the United States” (“WOTUS”) under the Clean Water Act: “relatively permanent” waters and “continuous surface connection” wetlands. That proposal drew roughly 220,000 public comments during its 45-day comment period, which closed on January 5, 2026.
Rather than proceed directly to a final rule, the Agencies went back to the drafting table. On September 9, 2026, the Agencies published a Supplemental Notice of Proposed Rulemaking (“SNPRM”) in the Federal Register, offering narrower alternative definitions for the terms that anchored their November 2025 proposal. The SNPRM does not withdraw or replace the original proposal; it supplements two discrete pieces of it and asks for additional public comment on those pieces alone. Comments on the SNPRM are due October 9, 2026.
The supplemental options include:
- Perennial Flow as the New Baseline for “Relatively Permanent”
- Narrowing “Continuous Surface Connection” to Require Perennial Surface Water in Wetlands
- Possible Elimination of “Adjacent” and “Abutting”
- Defined, Time-Limited Treatment of Drought and Seasonal Dry Spells
Narrowing “Relatively Permanent.”
The November 2025 proposal defined “relatively permanent” waters as those “standing or continuously flowing year-round or at least during the wet season” — a formulation that, as we noted in February, was intended to exclude ephemeral streams while still capturing many seasonal ones. Commenters pushed back hard on “wet season” as unworkable and legally unmoored from Sackett and the Rapanos v. United States, 547 U.S. 715 (2006) plurality opinion. In response, the SNPRM offers a stricter alternative: a water would be “relatively permanent” only if it is perennial, defined as having standing or continuously flowing water every day of the year under ordinary conditions. The Agencies propose two narrow exceptions to that year-round requirement: (1) anomalous events, such as drought or an unusual dry spell, which would not defeat jurisdiction if the interruption does not persist for more than five consecutive years (a period tied to the USACE’s five-year jurisdictional determination cycle); and (2) non-anomalous events, such as low tide or a regularly recurring dry spell, which would not defeat jurisdiction if the interruption lasts no more than a single 30-day period in any given year. The Agencies acknowledge that many intermittent streams treated as “relatively permanent” under the amended 2023 Rule would not meet this stricter standard.
Tightening “Continuous Surface Connection.”
The November 2025 proposal defined “continuous surface connection” as a wetland, lake, or pond that abuts a jurisdictional water and has surface water connecting to it at least during the wet season. The SNPRM’s supplemental option abandons the wet-season touching/abutting test for a perennial-connection standard: a continuous surface connection would exist only where a wetland has perennial surface water continuously connected to the jurisdictional water, such that it is difficult to tell where the jurisdictional water ends and the wetland begins. The same temporary-interruption allowances (drought, low tide, seasonal dry spells) described above for “relatively permanent” would apply to “continuous surface connection” as well. For wetland “mosaics,” only the portion of the wetland that is actually indistinguishable from the jurisdictional water would be jurisdictional, not the wetland complex as a whole.
Separately, the Agencies are soliciting comment on whether “adjacent” and “abutting” should be eliminated from the WOTUS definition entirely, on the theory that Sackett’s “indistinguishability” test already subsumes adjacency as a freestanding concept. Under this approach, the regulatory text would provide that wetlands are jurisdictional when “surface water in a wetland is continuously connected with the surface water in the jurisdictional water such that it is difficult to determine where the jurisdictional water ends and the wetland begins.” This text dispenses with any separate touching requirement in exchange for a pure hydrologic-connection inquiry. The Agencies expect that many wetlands currently treated as jurisdictional “adjacent wetlands” would not satisfy either version of this narrower standard, since most wetlands lack perennial surface water.
What the SNPRM Does Not Touch.
Practitioners should note what remains unchanged. The SNPRM does not revisit the November 2025 proposal’s treatment of traditional navigable waters, impoundments, the definition of “tributary,” or the exclusions for waste treatment systems, prior converted cropland, ditches, or the newly proposed groundwater exclusion. Nor does it disturb the proposed removal of “interstate waters” as a standalone jurisdictional category. Those portions of the original proposal remain under review based on the comments already received, and the Agencies have signaled they intend to finalize a single rule addressing both the November 2025 proposal and the SNPRM’s supplemental options together.
Practical Takeaways
If finalized, either alternative in the SNPRM would shrink the scope of federally jurisdictional tributaries and wetlands well below both the current baseline in the amended 2023 Rule and the November 2025 proposal itself, with the most pronounced effects on intermittent streams and non-perennial wetlands in arid and seasonally dry regions. Landowners, developers, and agricultural operators who calibrated Clean Water Act Section 404 permitting strategies around the November 2025 proposal should revisit those assumptions, particularly for projects involving intermittent drainages or wetlands lacking year-round surface water. Because the SNPRM leaves the bulk of the November 2025 proposal intact, this is best understood as a targeted recalibration rather than a fresh start, but it continues to move in one direction: narrower federal jurisdiction.
Given the short 30-day comment window closing October 9, 2026, stakeholders with an interest in the ultimate scope of “relatively permanent” and “continuous surface connection” should not wait for a final rule to weigh in. As with each prior swing of the WOTUS pendulum, informed and timely comments remain the most effective way to shape the final outcome rather than after-the-fact litigation.
