The supplemental proposal moves toward Florida’s recommendations on relatively permanent waters and continuous surface connections, but new implementation questions emerge, including a potential collision with one of the Corps’ most durable jurisdictional policies.
By STAFF REPORTS
The federal definition of “waters of the United States,” or WOTUS, took another significant turn this month.
On Sept. 9, the U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers (Corps) published a Supplemental Notice of Proposed Rulemaking that adds new alternatives to the WOTUS rule first proposed in November 2025. The definition determines the waters and wetlands subject to federal Clean Water Act jurisdiction, including the Section 404 dredge-and-fill permitting program.
The supplemental notice does not replace the November proposal. EPA and the Corps are still considering the earlier alternatives and the approximately 220,000 comments they received during the original comment period. Instead, the agencies have reopened two of the most important questions in the rule: what qualifies as a “relatively permanent” water and what type of “continuous surface connection” is required before a wetland becomes federally jurisdictional. Comments on the new alternatives are due Oct. 9. (Public Notice)
Those may sound like narrow definitional questions. They are not.
If adopted, the new alternatives would substantially reduce the number of streams and wetlands subject to federal Clean Water Act jurisdiction compared with current implementation. EPA and the Corps themselves acknowledge that most intermittent streams would likely fail the new relatively permanent water test and that a majority of wetlands currently jurisdictional as adjacent wetlands would not satisfy the supplemental continuous-surface-connection standard.
For Florida, however, a reduction in federal jurisdiction does not mean those wetlands cease to be regulated. Florida’s Environmental Resource Permitting program independently regulates dredging and filling in wetlands and other surface waters, including isolated wetlands which are categorically excluded from federal jurisdiction. The practical issue is therefore where the federal Section 404 boundary will sit within the considerably broader state regulatory framework.
From “Wet Season” to Perennial Waters
The November proposal attempted to define the “relatively permanent” standard derived from Sackett v. EPA by including waters that stand or flow continuously year-round or at least during the wet season.
That approach drew substantial criticism, including from Florida.
Florida joined a 20-state comment letter in January arguing that the wet-season concept could restore considerable discretion to jurisdictional determinations and sweep seasonal or intermittent features back into federal jurisdiction. The states urged the agencies to remove the wet-season language and more closely follow Sackett’s emphasis on relatively permanent waters and observable surface connections.
The supplemental notice moves substantially in that direction.
EPA and the Corps are now considering defining “relatively permanent” as “perennial bodies of water.” A new definition of “perennial” would mean having standing or continuously flowing water every day of the year under ordinary conditions. (Public Notice)
There are exceptions. A normally perennial water would not necessarily lose jurisdiction because of an anomalous event such as a drought. For ordinary, predictable interruptions such as low tide or a regularly occurring dry spell, however, the agencies propose a much more precise limit: one period of no more than 30 consecutive days in any given year.
The preamble provides an unusually specific example. A stream that normally dries for 30 consecutive days every June could remain perennial. A stream normally dry from June through August would not. More strikingly, a stream that experiences two separate ordinary 10-day dry periods during the same year would not qualify because the proposal allows only a single interruption.
Gunster attorneys Luna Phillips and Deborah Madden summarized the practical effect in a Sept. 9 client alert: an ordinary interruption longer than 30 days — or more than one such interruption during the relevant 12-month period — would take the water outside the proposed perennial standard.
On paper, that appears to be the kind of bright line many commenters requested. On the ground, things may be less simple.
Thirty Days Is Clear. Proving Thirty Days May Not Be.
EPA says the perennial alternative should make jurisdiction easier for landowners to understand. The preamble suggests that members of the public may be able to determine that a water is not jurisdictional “simply by observation” and without professional consultation. In discussing wetlands, the agencies go still further, suggesting that some determinations can be made by the “naked eye.”
The difficulty is that a person can observe whether a stream is flowing today. It is considerably harder to observe whether it flowed every day during the previous year, whether a dry period lasted 29 or 31 days, or whether it stopped flowing once or twice.
Herschel Vinyard, former Secretary of the Florida Department of Environmental Protection, raised that concern after reviewing the supplemental notice – “Will this be another back door ‘wet season’ challenge where nobody can prove the facts either way without monitoring the system for five years?”
The supplemental does not actually require five years of monitoring. EPA identifies a range of tools that could inform the determination, including field observations, aerial photography, the Corps’ Antecedent Precipitation Tool, NOAA climate information and the U.S. Drought Monitor. For drought, the agencies are considering treating only “extreme” and “exceptional” drought classifications as anomalous, potentially for as long as five years before the dry condition becomes the new normal.
But Vinyard’s larger evidentiary point remains.
Those tools can help establish whether a site visit occurred during unusually wet or dry climatic conditions. They do not necessarily establish whether a particular ungauged stream contained standing or flowing water on each day of an otherwise ordinary year.
The agencies acknowledge that there is no precise, scientifically established national basis for 30 days. They selected the period largely because a month provides a predictable and administrable dividing line.
That creates an interesting implementation problem. The proposal may establish a bright legal line without establishing equally bright evidence for locating that line in the field.
That concern is not limited to critics of a narrower WOTUS definition. Bloomberg Law reported sharply different reactions among attorneys following the proposal. Damien Schiff, who argued Sackett before the Supreme Court, described the perennial approach as substantially more administrable than the proposed wet-season test. Other practitioners questioned whether landowners or regulators can reliably reconstruct the precise duration and frequency of dry periods without substantial historical evidence.
That is likely to be one of the more useful subjects for the new comment period: not simply whether 30 days is the correct number, but what evidence should be sufficient to prove the jurisdictional fact.
The Bigger Change May Be Wetlands
The supplemental’s treatment of wetlands may ultimately be more consequential.
In Sackett, the Supreme Court held that federally jurisdictional wetlands must have a continuous surface connection to another jurisdictional water such that the wetland is, “as a practical matter,” indistinguishable from that water.
The November proposal would have defined a continuous surface connection as having surface water at least during the wet season while abutting, or touching, a jurisdictional water.
The new alternative goes considerably further.
EPA and the Corps are now seeking comment on a definition requiring perennial surface water in the wetland that is continuously connected with surface water in the jurisdictional water, such that it is difficult to determine where the waterbody ends and the wetland begins. (Public Notice)
Phillips and Madden describe the potential effect succinctly: “mere physical abutment or adjacency would no longer suffice” under the supplemental approach.
The agencies are also asking commenters to consider an even more fundamental change. They solicit comment on removing “adjacent” and “abutting” as operative concepts and rewriting the adjacent-wetlands category around Sackett’s “indistinguishability” language.
Under that alternative, only the portion of a wetland that is indistinguishably part of the jurisdictional water because of continuous surface water would itself be federally jurisdictional.
That could mark a significant departure from longstanding Corps practice.
Enter the Corps’ “One Wetland” Policy
The contrast is particularly visible in Florida.
Under what the Corps itself calls the “One Wetland Memo,” physically separated portions of wetlands can be treated as one wetland if sufficient evidence shows that they were once part of a contiguous wetland and continue to function as a single wetland system. The evidence can include culverts, surface or shallow subsurface hydrology, similarities in vegetation and soils, topography, historic aerials, and other indicators.
The jurisdictional consequence is important: current headquarters guidance states that the agencies consider the entire wetland adjacent if any part of the wetland is adjacent to a jurisdictional water. (US EPA)
A recent Florida case illustrates how far that principle can reach.
In the case of M BB Grove, LLC, the Corps’ Jacksonville District determined that approximately 1.06 acres of wetlands on a Winter Garden property were part of the much larger Davenport Creek Swamp. The District treated wetland segments divided by six road crossings as one wetland system that ultimately reached Davenport Creek and, downstream, Reedy Creek. Its theory was not that the culverts themselves created the continuous surface connection required by Sackett. Rather, the District concluded that the project wetland and the distant abutting wetland were all portions of one wetland. If that premise was correct, the entire wetland could be jurisdictional. (SAD M BB Grove)
The Corps’ South Atlantic Division did not reject that legal framework when the landowner appealed.
Instead, in a March 2026 decision, the Division found that Jacksonville had not assembled enough site-specific evidence to prove that the wetland remained one functioning system across the six road crossings. It remanded the determination and instructed the District to perform a crossing-by-crossing evaluation, including potential surface and shallow subsurface connections. The decision expressly noted that the One Wetland Memo had not been rescinded by the Corps’ March 2025 continuous-surface-connection guidance. (SAD M BB Grove)
The logic bears some resemblance to the aggregation approach that characterized older WOTUS practice, although it is legally distinct from the “significant nexus” test rejected in Sackett. Instead of asking whether a group of wetlands collectively has a significant effect on a downstream water, the One Wetland approach first defines a sufficiently large physical wetland unit and then applies federal adjacency to that entire unit – even its most remote parts, miles away from a jurisdictional surface water.
In M BB Grove, the Division summarized Jacksonville’s theory directly: if the project wetland was part of the larger wetland that directly abutted a jurisdictional water at its southern extent, the entirety of the single wetland was jurisdictional. (SAD M BB Grove)
Now compare that with the alternative EPA and Army Headquarters just placed on the table: only the portion of the wetland that is indistinguishably part of the jurisdictional water would itself be jurisdictional.
Those approaches are difficult to reconcile as jurisdictional doctrines.
The Corps could presumably continue using “one wetland” principles to determine the ecological or delineated extent of a wetland. But if the supplemental “indistinguishability test” becomes final rule, the existing proposition that federal jurisdiction extends throughout that entire wetland because one remote portion abuts WOTUS would appear to require repeal or at least substantial revision.
In March of this year, the Division was directing Jacksonville to develop better evidence to determine whether jurisdiction could extend through an enormous wetland complex despite miles of distance and six road crossings. Six months later, Army Headquarters and EPA are formally considering a framework under which the federal jurisdictional line could instead stop within the wetland itself when the required perennial surface-water connection ends.
That is potentially a sea change in how the Corps determines federal wetland jurisdiction.
National Reaction Reflects the Stakes
The supplemental has generated predictable disagreement over what that narrower federal boundary would mean.
The American Farm Bureau Federation welcomed the proposal, emphasizing the need for farmers and landowners to understand where federal jurisdiction begins and ends. The National Stone, Sand & Gravel Association similarly focused on permitting certainty and delays associated with unclear jurisdictional standards. (Farm Bureau)
Environmental organizations see the same jurisdictional change from the opposite direction. The Natural Resources Defense Council estimates, based on its own GIS modeling, that as much as 94 percent of wetlands in the continental United States could fall outside federal Clean Water Act jurisdiction under the perennial approach. That figure is NRDC’s estimate, not EPA’s. (NRDC)
EPA itself does not attempt to quantify the national wetland acreage affected. The agencies say existing datasets are not reliable enough to map WOTUS jurisdiction precisely. They nevertheless anticipate significant reductions in federal jurisdiction, particularly for intermittent streams and adjacent wetlands.
Much of the broader debate describes those changes as either expanding or removing “wetland protections.” That shorthand can obscure an important part of the Clean Water Act’s structure.
WOTUS establishes the scope of federal Clean Water Act jurisdiction. It does not establish the outer limit of state authority over wetlands.
EPA emphasizes that distinction in announcing the supplemental, stating that waters outside federal jurisdiction remain subject to state, Tribal and local authority under the Act’s cooperative-federalism framework and the Constitution. The supplemental itself points to Congress’ recognition in CWA Section 101(b) of the “primary responsibilities and rights of States” over land and water resources. At the same time, EPA acknowledges that state programs vary and that some states have fewer regulatory resources or legal authority than others. (US EPA)
Florida is therefore an important example of why “non-WOTUS” and “unprotected” are not interchangeable terms.
Florida’s ERP program regulates activities in wetlands and other surface waters independently of the federal WOTUS definition. A wetland removed from federal Section 404 jurisdiction will still require state authorization, avoidance and minimization, and mitigation under Florida law.
For Florida applicants, the change would instead alter the administrative burden: which waters and wetlands require a federal Section 404 authorization in addition to the state ERP process.
Florida Got Much of What It Asked For — But the Details Matter
Florida’s January comments objected specifically to the November proposal’s wet-season methodology and urged the agencies to more directly incorporate Sackett’s continuous-surface-connection and indistinguishability requirements.
The September supplement moves substantially toward those positions. It replaces the wet-season concept with a new perennial-water test and considers making Sackett’s indistinguishability language the central test for federal wetland jurisdiction.
But the supplemental also demonstrates why drawing a clear jurisdictional line and implementing one are different exercises.
The perennial standard is much easier to state than “wet season.” Whether the proposed 30-day exception can be reliably established for ungauged waters is less certain.
Likewise, the proposed wetland standard appears considerably closer to the language of Sackett, but adopting it would force the Corps to reconcile the new rule with implementation policies — particularly its One Wetland policy — that have continued to support jurisdiction over much more remote wetland areas.
Those are precisely the kinds of questions the supplemental comment period should address.
EPA Administrator Lee Zeldin has said the agency’s objective is a durable WOTUS rule that follows the law and ends regulatory uncertainty. The agencies now have comments from their original proposal, another 30-day comment period underway, and substantially different alternatives before them. (US EPA)
Whether the final rule actually produces that durability may depend less on another definition of WOTUS than on whether EPA and the Corps can explain, in practical terms, how regulators and landowners are supposed to find the line.
