Wetlands: What They Mean for a Piece of Land

What actually makes something a "wetland"

Wetlands are areas inundated or saturated by surface or ground water often enough and long enough to support vegetation adapted to grow in saturated soil -- swamps, marshes, bogs, and similar areas. That's the definition the Army Corps of Engineers and EPA have used since the 1970s for regulatory purposes, and it doesn't require standing water year-round or even most of the year.

In practice, regulators determine whether a specific spot meets that definition using the 1987 Corps of Engineers Wetlands Delineation Manual, which looks at three things together: hydric soils, wetland-adapted vegetation, and evidence of wetland hydrology. An area has to show all three to be delineated as a wetland. This means a patch of land can look dry on the surface most of the year and still be a legally regulated wetland -- soil and vegetation evidence carries as much weight as visible water.

You can't determine this from a listing photo or even a walk-through. If a parcel has any low-lying, seasonally wet, or densely vegetated-in-a-particular-way area, the only way to know for certain is a wetland delineation by a qualified consultant, or a formal jurisdictional determination from the Army Corps district office.

Why it matters: the Clean Water Act, not local zoning

Wetland regulation is separate from, and can be more restrictive than, your local zoning. Section 404 of the Clean Water Act regulates the discharge of dredged or fill material into "waters of the United States," and where a wetland is legally connected to those waters, that includes filling, grading, or in some cases even clearing it. Local zoning might say your lot is buildable; federal wetland jurisdiction is a completely separate question with its own permitting authority -- the Army Corps of Engineers, with EPA oversight.

If a Section 404 permit is required, activities usually fall under either a faster, standardized "general permit" (called a Nationwide Permit for common, lower-impact work) or a slower, project-specific "individual permit" that can involve months of review, mitigation requirements, and sometimes require you to restore or create wetlands elsewhere to offset the loss.

The 2023 Sackett decision changed which wetlands are covered

For decades, "waters of the United States" was interpreted broadly, including wetlands with only a "significant nexus" to a navigable water -- meaning they affected its chemical, physical, or biological integrity, even without a direct surface connection. In Sackett v. EPA (2023), the Supreme Court rejected that test. The Court held that only wetlands with a continuous surface connection to a relatively permanent body of water -- meaning the wetland is physically adjoining that water body, not just nearby or seasonally linked -- are subject to federal Clean Water Act jurisdiction.

In March 2025, EPA and the Army Corps issued joint guidance to field staff clarifying what "continuous surface connection" means in practice: the wetland must be physically touching a jurisdictional water, and that connection has to be sustained, not occasional or seasonal. As of late 2025 and into 2026, EPA and the Corps have proposed a formal rule to rewrite the regulatory definition of "waters of the United States" to match Sackett; that rulemaking was still in progress as of this guide's last review, with a public comment period that closed in January 2026.

The practical result for a land buyer: many wetlands that would have required a federal permit before 2023 -- particularly isolated wetlands and ones connected only by groundwater, occasional flow, or a man-made ditch -- may no longer fall under federal jurisdiction. But "may no longer" is doing real work in that sentence. Independent estimates of how much wetland acreage lost federal protection after Sackett vary enormously, from under one-fifth to a large majority of the nation's remaining wetlands, depending on how "continuous surface connection" gets applied on the ground. That range itself tells you the rule is still being worked out case by case.

What losing federal jurisdiction does -- and doesn't -- change

A wetland falling outside federal Clean Water Act jurisdiction after Sackett is not necessarily unregulated. Many states and some local governments have their own wetland protection laws that are independent of, and in some cases broader than, federal law -- these were not affected by Sackett at all. A wetland that's no longer a federal 404 matter can still require a state or local wetland permit, so "not federally jurisdictional" is not the same as "no permit needed."

• Get a wetland delineation (a licensed environmental consultant walks the property and flags boundaries) before you close, not after.
• Ask the Army Corps district office for a jurisdictional determination if the delineation finds anything ambiguous -- it's the only way to get a binding federal answer.
• Separately check your state environmental agency, since state wetland law can apply even where federal law doesn't reach post-Sackett.
• Assume nothing based on the county zoning map alone -- wetland boundaries are a hydrology and soils question, not a zoning-district question.

What this means for your purchase

If a wetland delineation or the county's wetland inventory flags part of a parcel, that doesn't automatically mean walk away -- it means get specific. Ask how many buildable, non-wetland acres remain, whether a permit would be needed for your intended use, roughly what that permit process would cost and take, and whether mitigation (creating or restoring wetland elsewhere) would be required. Make wetland status a contingency in your purchase agreement, the same way you would a perc test, so you can walk away if the answer is bad news.