On September 4, 2026, the U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers issued a supplemental notice of proposed rulemaking (SNPRM) seeking additional public input on the definition of “waters of the United States” (“WOTUS”), and ultimately the scope of federal jurisdiction under the Clean Water Act (CWA).[1] The proposal builds on the agencies’ November 2025 rulemaking and the U.S. Supreme Court’s decision in Sackett v. EPA.[2] Most notably, the supplemental proposal would limit the WOTUS definition to perennial waters, under which tributaries would generally need to have standing or continuously flowing water every day of the year under ordinary conditions to qualify as “relatively permanent” waters. For wetlands, federal jurisdiction would generally require perennial surface water that is continuously connected to an otherwise jurisdictional water.
If adopted, the supplemental approach could significantly reduce the scope of federal CWA jurisdiction, particularly for intermittent streams and wetlands that currently qualify based on their adjacency to jurisdictional waters. The agencies anticipate that the greatest reductions could occur in arid regions and that the CWA Section 404 permitting program could see fewer permits and reduced mitigation requirements. At the national scale, the proposal may provide greater certainty for landowners, developers, and regulated entities, but it also could shift greater responsibility to states and Tribes, potentially resulting in greater variation among jurisdictions.
Specifically for Ohio, this could create some regulatory uncertainty. The definition, as proposed in the SNPRM, will likely result in more state regulation of direct impacts to wetlands, which would be covered by Ohio’s Isolated Wetland Permitting Program. However, any direct impact on intermittent streams might require additional state-level action. Intermittent streams would still be protected under state law, but there is no state-level permitting mechanism currently in place that could be used to authorize such impacts. Two options to address this are 1) Ohio could either implement a permitting program for intermittent stream impacts; or 2) redefine the definition of state waters to exclude intermittent streams, similar to what the state did after ephemeral streams were excluded from federal jurisdiction.
Comments are due on October 9, 2026, 30 days after the SNPRM was published in the Federal Register. The federal government received 220,000 comments to the November rulemaking, and one would expect that the federal government will receive a large number of comments to this SNPRM. Furthermore, it is almost assured that if the rule is enacted as proposed here, there would be legal challenges to the final rule. If you have questions about state or federal permitting under the Clean Water Act or Ohio laws, please contact Nat Morse or your Vorys attorney.
[1] https://www.federalregister.gov/documents/2026/09/09/2026-18317/updated-definition-of-waters-of-the-united-states
[2] See this earlier post for additional background: https://energyenvironmentalblog.vorys.com/wotus-whiplash