Whither WOTUS? What The Regulated Community Should Know About The Draft Revisions To The WOTUS Rule

The Clean Water Act prohibits the discharge of pollutants from a point source to navigable waters without a permit. (33 USC 1311). This makes interpreting "navigable waters" key because this term defines the jurisdictional bounds of the Clean Water Act. Yet, the Act simply defines "navigable waters" as "the waters of the United States, including the territorial seas." (33 USC 1362(7)). Thus began the decades-long saga of the "waters of the United States," or "WOTUS," defined through multiple agency rulemaking bouts and no fewer than four journeys to the U.S. Supreme Court.

In the latest chapter, the EPA and the U.S. Army Corps of Engineers published draft revisions to the regulatory definition of "waters of the United States" on Nov. 20, 2025. 90 Fed. Reg. 52498. This is the second revision to the rule in the two-and-a-half years since the Supreme Court in Sackett v. Environmental Protection Agency held that WOTUS is limited to relatively permanent tributaries of traditional navigable waters, and wetlands with a continuous surface connection to such tributaries. 598 U.S. 651 (2023). Public comments on the draft rule are due by Jan. 5, 2026.

The draft revisions follow the saga's first actual foray into rhyme, as the notice of intent to engage in the rulemaking was entitled, "WOTUS Notice: The Final Response to SCOTUS." 90 Fed. Reg. 13428 (March 24, 2025). Consistent with the theme of finality, the draft rule's purpose was to "clarify the scope of Federal jurisdiction" in light of Sackett. 90 Fed. Reg. 52499.

Does the draft rule prevail in these twin challenges of clarity and finality? Significant aspects of the draft rule include:

• The key concept from Sackett of "relatively permanent" is defined as surface water that has standing or flowing water year-round or at least during the "wet season." Similarly, the definition of "continuous surface connection" means a wetland that abuts a jurisdictional water and has surface water at least during the "wet season." However, "wet season" remains undefined.
• The draft rule has an exclusion for ditches "constructed or excavated entirely in dry land." However, the preamble asserts that a ditch that connects to a jurisdictional tributary is not itself jurisdictional. It is unclear how a ditch constructed entirely in dry land could physically connect to a jurisdictional tributary.
• The draft rule provides that jurisdiction over a tributary is severed by reaches of non-relatively permanent flow. However, it also introduces an exception when the tributary is "part of a water transfer."

Although "wet season" is not defined in the draft rule itself, its potential application is discussed at length in the Preamble. Importantly, the concept may be challenging to apply in the arid west. The preamble discusses the fact that the "wet season" may occur during runoff from melting snowpack. However, this could be difficult to apply in practice. For instance, in Colorado, many plains streams do not flow in response to snowpack runoff at all. In mountain streams, the snowpack runoff period may be measured in weeks rather than months, and the timing may be variable from year to year. And, in many arid west states, surface water may occur during summer monsoons, but the monsoon season is also highly variable from year-to-year in terms of precipitation amounts and timing.

Meanwhile, the states have not stood still in their responses to Sackett. In the period following the publication of the draft WOTUS rule, western state developments include:

• New Mexico: The New Mexico Environment Department commenced the formal rulemaking process for amendments to the state's regulations to create a discharge permit and dredge and fill permit program in a petition to the state's Water Quality Control Commission on Nov. 24, 2025. This action follows legislation and informal regulatory activities earlier in 2025 (read more here). The petition requests a rulemaking hearing in June or July of 2026.
• Colorado: The Colorado Water Quality Control Commission completed a three-day rulemaking hearing on December 8-10, 2025, in which the WQCC adopted Regulation 87 creating a new state permitting program for discharges of dredged or fill material (Reg. 87 Dredge and Fill). Key issues resolved in the hearing included (a) standards for mitigation of ephemeral and intermittent streams; (b) projects requiring dual jurisdiction between state and federal programs; (c) whether to include a broad scale public interest review; (d) definition of a state-specific exclusion for wetlands adjacent to and supported by ditches; (e) the procedure to determine a project's purpose and need, practicable alternatives and the subsequent alternatives analysis without injuring water rights; and (f) the fee structure for the program, which deviates significantly from the Army Corps' fees.
• Arizona: The Arizona Department of Environmental Quality (ADEQ) has developed a list called the "Protected Surface Waters List" (PSWL), which includes both WOTUS and Non-WOTUS waters. If a water meets the federal CWA definition of a WOTUS, it is automatically included on the PSWL and regulated as a federally protected water. Waters deemed not to be a WOTUS under the current federal definition may be regulated through ADEQ's Surface Water Protection Program (SWPP) as a Non-WOTUS Protected Surface Water if that water meets the definition of a state protected surface water, in accordance with Arizona Revised Statutes (A.R.S) §49-221(G). The PSWL is advisory only and does not constitute a final agency action or a jurisdictional determination for any water. It was created as part of the SWPP to increase regulatory clarity in Arizona. ADEQ does not have current plans to conduct a formal rulemaking to update the lists until guidance for a new WOTUS definition is finally released by the federal agencies (the EPA and United States Department of the Army) in response to the Sackett  decision. (See 90 Fed. Reg. 52498, November 20, 2025). A list of waters regulated as WOTUS can be found in the Arizona Administrative Code Title 18, Chapter 11 (R18-11), Article 2 in Table B and Table C. A list of Non-WOTUS Protected Surface Waters can be found in R18–11, Article 2, Table A. If additional legal challenges are filed against the new WOTUS proposal by the federal agencies, then ADEQ will delay any final PWSL formal rulemaking.

What the Regulated Community Should Know Moving Forward

A significant issue going forward will be the relationship between state and federal programs, particularly given the differences between state definitions of "state waters" subject to regulation and the ever-shifting definition of WOTUS. Every action on the definition of WOTUS should be anticipated to prompt a reaction, at least in some states. Regulated entities should engage regarding both the federal WOTUS rule and  in state processes to ensure their concerns are heard.

Clark Hill supports clients with active NPDES permits, those who seek permits for discharge of pollutants or for discharge of dredged or fill material, and others who may be impacted by federal and state permitting programs.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.