EPA, Army Corps Proposes Redefining CWA Jurisdiction Scope

If there were an Olympic event for regulatory whiplash, “waters of the United States” would already have a gold medal, a silver medal, and probably a sponsorship deal. Few environmental law issues have swung back and forth as dramatically as the question of which wetlands, streams, ditches, ponds, and other features fall under federal authority through the Clean Water Act (CWA). Now the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers are taking another turn on the policy carousel with a proposal to redefine the scope of Clean Water Act jurisdiction.

As of March 19, 2026, the agencies have proposed a new rule, not finalized one, that would narrow federal jurisdiction and more closely align the regulatory definition with the U.S. Supreme Court’s 2023 decision in Sackett v. EPA. The proposal is a big deal because the definition of CWA jurisdiction determines when federal permits are required, when enforcement risk kicks in, and when states and tribes become the primary line of defense for water protection. In plain English: this is not just a lawyer problem. It affects farmers, builders, energy developers, transportation agencies, landowners, environmental groups, and anyone who enjoys not living next to a flood-prone mud pit.

Why the CWA Jurisdiction Debate Matters So Much

The Clean Water Act is one of the country’s most important pollution-control laws, but its reach depends on a deceptively small phrase: “waters of the United States,” often shortened to WOTUS. That phrase helps define which waters are covered by federal programs such as Section 402 discharge permits, Section 404 dredge-and-fill permits, Section 401 water quality certification, oil spill prevention under Section 311, and water quality planning under Section 303.

So when EPA and the Army Corps redraw the jurisdiction line, they are not just changing vocabulary. They are changing whether a project needs a federal permit, whether a landowner needs to call consultants before moving soil, whether wetlands are subject to federal protection, and whether a state must step in if federal authority pulls back. That is why every WOTUS rule feels less like a technical update and more like a nationwide zoning argument with mud on its boots.

How We Got Here: A Brief WOTUS Timeline

The current proposal did not appear out of nowhere. It is part of a long-running fight over how far the Clean Water Act reaches beyond traditionally navigable waters. Over the last decade, the definition has changed repeatedly through Obama-era rulemaking, the Trump administration’s 2020 Navigable Waters Protection Rule, the Biden administration’s 2023 rule, and a 2023 conforming rule issued after the Supreme Court decided Sackett.

The real turning point for today’s proposal was Sackett v. EPA. In that case, the Supreme Court sharply limited federal jurisdiction over wetlands. The Court said the Clean Water Act covers only wetlands that have a continuous surface connection to waters that are themselves waters of the United States, making it difficult to tell where the water ends and the wetland begins. That ruling knocked out the broader “significant nexus” approach that had supported federal regulation of many wetlands and other aquatic features.

After Sackett, EPA and the Army first issued a conforming rule in 2023 and then, in March 2025, released implementation guidance on “continuous surface connection” while also opening a public docket and holding listening sessions. Those steps signaled that the agencies believed more than a patch job was needed. The November 2025 proposal is the result: an attempt to rewrite the rule in a way the agencies say is clearer, more durable, and more faithful to the Supreme Court’s direction.

What the New Proposal Actually Does

The heart of the proposal is simple: it narrows the scope of federal jurisdiction by tightening definitions, revising exclusions, and removing categories the agencies now believe stretch beyond the Clean Water Act as interpreted by the Supreme Court. But the details matter, and they matter a lot.

1. It would remove “interstate waters” as a standalone category

For years, waters crossing state lines could be treated as federally jurisdictional simply because they were interstate waters. The proposal would remove that category as an independent basis for jurisdiction. In the agencies’ new view, a water does not become federally regulated just because it crosses a border. It still has to fit within the narrower jurisdictional framework grounded in traditional navigable waters, qualifying tributaries, qualifying impoundments, or qualifying adjacent wetlands and connected waters.

That is a major shift because it reflects the agencies’ reading that the Clean Water Act’s operative term is “navigable waters,” not “interstate waters” standing alone. For property owners and project developers, that change could reduce federal reach. For regulators and environmental advocates, it raises concern that some cross-border waters may lose federal protection unless they independently satisfy the revised test.

2. It would define “relatively permanent” for the first time

The proposal would add a formal definition of “relatively permanent,” a phrase that has become central after Sackett. Under the proposed approach, jurisdiction would focus on standing or continuously flowing surface waters that flow year-round or at least during the wet season. The agencies make clear that ephemeral featuresthose that flow only in direct response to rainfall or snowmelt eventswould not be included.

That matters for streams and tributaries in arid regions, seasonal drainage systems, and landscapes where water shows up dramatically but briefly, like an overenthusiastic houseguest who leaves right after the snacks are gone. If a feature carries water only after storms, it is likely out. If it has persistent flow through the wet season or year-round, it has a much better chance of being in.

3. It would tighten the definition of “tributary”

The proposed rule says jurisdictional tributaries must connect to traditional navigable waters either directly or through other features that provide predictable and consistent flow. This is another narrowing move. The idea is to avoid sweeping in channels that are too disconnected, too temporary, or too speculative in their relationship to downstream navigable waters.

In practice, this could leave some intermittent or seasonal channels outside federal jurisdiction, especially where flow is broken by non-relatively permanent reaches. But tributaries with persistent wet-season or year-round flow that ultimately connect downstream through features like culverts or other consistent conveyances may still qualify.

4. It would redefine “continuous surface connection” for wetlands

This is one of the proposal’s most important features. The agencies would define “continuous surface connection” to mean two things at once: the wetland must abut a jurisdictional water, meaning it must touch it, and it must have surface water at least during the wet season. That creates a two-part test for adjacent wetlands.

Translation: if a wetland is near a covered stream but separated by a berm, road, upland strip, or other break such that it does not actually touch the jurisdictional water, it likely will not qualify. Likewise, if it touches but lacks the required surface water conditions, it may still fall out. The agencies also asked for comment on an even stricter alternative, which shows the final rule could become narrower still.

5. It would revise the ditch exclusion

Ditches have long been one of the most maddening parts of WOTUS policy because not every ditch is just a ditch. Some behave like jurisdictional waters, while others are plainly engineered drainage features. The proposal tries to draw a cleaner line by defining “ditch” and excluding ditches constructed or excavated entirely in dry land.

That means many roadside ditches, agricultural ditches, and other man-made conveyances dug in dry ground would be excluded, regardless of flow. But ditches built in wetlands are treated differently. If the ditch was constructed in a wetland, it is not automatically excluded just because somebody gave it straight edges and a practical-sounding name.

6. It would revise the prior converted cropland exclusion

The agencies propose to maintain the exclusion for prior converted cropland but revert to the 2020 rule’s approach. Under that framework, land would lose its prior converted cropland status only when it has been abandoned and has reverted to wetlands. The proposal describes abandonment as land that has not been used for, or in support of, agricultural purposes in the preceding five years.

This point is especially important for farmers and ranchers because it aims to provide more certainty and prevent agricultural producers from losing exclusions simply because they adopted conservation practices or changed operations over time. It also reduces sole reliance on USDA determinations for Clean Water Act purposes.

7. It would clarify the waste treatment system exclusion and add an explicit groundwater exclusion

The proposal would clarify that waste treatment systems remain excluded and would add an express exclusion for groundwater, including groundwater drained through subsurface drainage systems such as agricultural tile drains. EPA and the Corps say groundwater has never been jurisdictional under the statute, but they want the rule to say so more clearly.

There is one important nuance: surface expressions of groundwater can still matter. If groundwater emerges and becomes part of a relatively permanent surface water feature, that resulting surface water may be analyzed differently. So no, slapping the word “groundwater” on a drainage issue does not automatically make federal questions disappear like a magic trick.

What This Proposal Would Mean in the Real World

If finalized largely as proposed, the rule would shrink the number of waters and wetlands subject to federal Clean Water Act jurisdiction. That would likely mean fewer federal permits, lower compliance costs for some landowners and project sponsors, and greater reliance on states and tribes to regulate waters that fall outside federal coverage.

Supporters say that is exactly the point. They argue that the current and prior rules created uncertainty, extended federal authority too far, and forced landowners to navigate expensive permitting processes for features that Congress never intended Washington to regulate. For agriculture, development, mining, energy, and infrastructure interests, the appeal is obvious: more predictability, fewer surprises, and a clearer boundary between federal authority and local land use.

Critics, however, see a very different story. They argue the proposed rule could leave many wetlands and smaller streams without federal protection, especially in states that do not have robust independent wetlands programs. EPA’s own regulatory analysis acknowledges that a narrower jurisdictional scope could indirectly reduce ecosystem services if states or tribes do not fill the gap. Those services include habitat, flood attenuation, and water-quality functions that do not stop working just because a regulation stops noticing them.

In other words, the policy argument comes down to a familiar American question: is the bigger problem regulatory overreach or regulatory retreat? The answer depends heavily on where you siton a bulldozer, in a state agency office, in a duck blind, on a farm, or in a neighborhood that floods every spring.

Examples of How the Proposal Could Apply

Consider a wetland that directly touches a qualifying stream and holds surface water throughout the wet season. Under the proposal, that wetland has a strong argument for being jurisdictional because it satisfies both the touching requirement and the wet-season surface water requirement.

Now consider an isolated wetland separated from the nearest stream by upland or a man-made barrier, even if it provides important ecological benefits. Under the proposed rule, that wetland likely falls outside federal jurisdiction because it is not “indistinguishable” from a jurisdictional water through a continuous surface connection.

Or take a roadside ditch dug entirely in dry land. Under the proposal, that ditch would generally be excluded. But a ditch excavated through a wetland may not enjoy the same safe harbor. And a tile drainage system moving groundwater below the surface would be expressly excluded as groundwater, not transformed into WOTUS merely because the water is moving through a man-made system.

Will the Proposal End the WOTUS Wars?

Probably not. Asking whether this rule will end WOTUS litigation is a little like asking whether one umbrella will end hurricane season. The proposal may bring greater clarity in some respects, especially by adding formal definitions for terms that have been doing far too much unpaid labor. But it also raises new questions about wet-season flow, severed tributary networks, wetland hydrology, and how much narrowing the Supreme Court actually requires.

There is also the reality that the agencies are already operating under a patchwork system because different standards apply in different states due to ongoing litigation. Even if the rule is finalized, lawsuits are highly likely. That means the regulated community could still face uncertainty, just with updated vocabulary and fresh briefing schedules.

Still, the proposal is significant because it shows where the agencies want to draw the line: closer to Sackett, closer to a bright-line test, and further away from broader federal jurisdiction over wetlands and small waters. Whether that line proves legally durable is the next chapter in a very long story.

What the Proposal Feels Like on the Ground: Real-World Experiences Around CWA Jurisdiction

To understand this proposal, it helps to step away from the Federal Register for a minute and think about how jurisdiction questions actually feel in everyday work. For many people, the WOTUS debate is not abstract. It shows up as a survey flag in a field, a consultant invoice, a delayed permit, a redesign of a subdivision, or a nervous phone call that starts with, “We found standing water on the site.” Glamorous? No. Important? Absolutely.

For farmers, the experience is often one of trying to do ordinary land management while navigating rules that can seem to change every few years. A producer may look at a ditch or low spot and see a practical drainage feature that has been part of the property forever. A federal regulator may see a more complicated hydrologic story. The proposed rule is designed to make that boundary easier to understand, especially for ditches, tile drains, and prior converted cropland. From the agricultural perspective, that kind of clarity is not just a policy win; it is a budgeting win, a planning win, and a stress-reduction win.

For developers, engineers, and homebuilders, the experience is usually about time and risk. A project can move smoothly until someone determines that a wetland or tributary on the property may be federally jurisdictional. Then timelines stretch, costs climb, and design plans start doing yoga-level contortions to avoid impacts. A narrower jurisdictional rule could reduce some of that friction. But it would not eliminate the need for careful site review. It would simply change which features trigger the federal process and which ones are more likely to be handled at the state or local level.

For environmental groups and conservation professionals, the experience is often one of watching small waters get underestimated because they are small, seasonal, or inconveniently located where somebody wants to build something profitable. Many wetlands do important work even when they do not look dramatic enough for a postcard. They store floodwater, filter runoff, support wildlife, and help downstream waters stay healthier. From that vantage point, a narrower rule can feel less like clarity and more like retreat.

State regulators occupy an especially awkward middle seat. When federal jurisdiction narrows, pressure often shifts to the states. In states with strong wetland and water protections, that may be manageable, though still resource-intensive. In states without comprehensive programs, the practical result can be a real coverage gap. That is why this proposal is also a federalism story. It is not just about what EPA and the Corps regulate. It is about who regulates what after they step back.

And for consultants, lawyers, and permit specialists, the experience is one of permanent déjà vu. Every new rule promises clarity. Every new lawsuit promises uncertainty. And somewhere in the middle, real people are trying to figure out whether a piece of land includes a jurisdictional feature or just a very annoying puddle with legal ambitions. The newest EPA and Army Corps proposal may make that answer easier in some cases. But it also reminds us that in Clean Water Act law, the map is never just a map. It is money, power, ecology, and a whole lot of mud.

Conclusion

The EPA and Army Corps proposal to redefine the scope of Clean Water Act jurisdiction is one of the most consequential water-law developments in the country right now. It narrows federal reach, formalizes key post-Sackett definitions, removes interstate waters as a standalone category, tightens treatment of tributaries and wetlands, and expands clarity for exclusions involving ditches, groundwater, waste treatment systems, and prior converted cropland.

For regulated industries and many landowners, the proposal promises a more workable rulebook. For environmental advocates and states that rely heavily on federal wetland oversight, it raises serious questions about lost protection and uneven backstops. One thing is clear: the fight over federal water jurisdiction is not over. It has simply entered another round, wearing slightly different boots.

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