A parcel in North Carolina with a small polygon of mapped wetland used to be a straightforward federal issue. If the wetland connected to a traditionally navigable water, the Army Corps had jurisdiction under Section 404 of the Clean Water Act. A developer who wanted to fill needed a permit. That permit, depending on acreage and type, ran anywhere from six weeks to eighteen months.
Then came Sackett v. EPA in May 2023. The Supreme Court narrowed the definition of "waters of the United States" significantly. A lot of wetlands that used to be federally regulated are no longer federally regulated.
The narrative that followed was that wetlands no longer mattered for development. That narrative is wrong, and acquisition teams that treat it as right are walking into regulatory traps.
What Sackett actually said
The Sackett decision held that federal jurisdiction under the Clean Water Act extends to wetlands with a continuous surface connection to other jurisdictional waters, such that the wetland is indistinguishable from the water. The prior legal test, significant nexus, was rejected.
Plainly: the wetland has to be touching a federally regulated water for the federal protection to apply. Isolated wetlands, vernal pools, and many small headwater wetlands are no longer federally jurisdictional.
The Army Corps has been updating its practice to reflect the ruling. Approved jurisdictional determinations issued since late 2023 are visibly narrower than those issued before.
What Sackett did not change
State wetland laws are untouched. The federal narrowing does nothing to state protections, and several states have protections that are stricter than the federal baseline.
Massachusetts, New Jersey, Minnesota, Michigan, Washington, and California all have state wetland programs that protect wetlands the federal program no longer reaches. A parcel in any of these states with a mapped wetland is not automatically clear.
Local programs matter too. A county in Florida or a municipality in Maryland may have its own wetland protection ordinance layered on top of state and federal rules. These are not uniform. Each one needs to be checked.
NWI is a map, not a determination
The National Wetlands Inventory, maintained by US Fish and Wildlife, is the most-cited wetland dataset. It is also widely misunderstood.
NWI is a remote-sensing-based estimate of wetland extent, developed from aerial photography and supplemented with field data of varying age. It is a map. It is not a jurisdictional determination.
A polygon on an NWI map may or may not meet the legal criteria for a wetland under federal or state law. The only way to know is to have a wetland scientist delineate the boundary on the ground and, if federal jurisdiction is in play, to submit a jurisdictional determination request to the Army Corps.
A clean acquisition strategy does the reverse check too. The absence of an NWI polygon does not mean no wetland. NWI misses small wetlands, recently created wetlands, and wetlands under forest canopy. A ground survey can find what the map missed.
Preliminary versus approved JDs
When federal jurisdiction is at issue, the Army Corps offers two kinds of jurisdictional determination.
A preliminary jurisdictional determination, PJD, assumes that the mapped wetlands are jurisdictional. It is faster. It is not a legal conclusion. A permittee who does not want to fight about jurisdiction can proceed on a PJD and get to a permit decision faster.
An approved jurisdictional determination, AJD, is a legal determination of jurisdiction. It takes longer. It is appealable. In the current post-Sackett environment, an AJD is often worth the wait, because a parcel that the Corps determines is not jurisdictional is off the federal hook entirely.
Timelines vary by district. The Los Angeles district is fast. The Mobile district is slow. A deal where the timeline matters should account for the variance.
The acquisition workflow
Pull the NWI layer for the parcel. If no polygons are present, do not declare victory. Note it, pull the Soils layer for hydric inclusions, and flag the parcel for a ground-level reconnaissance before any major site work.
If NWI polygons are present, identify the approximate acreage and the classification. A forested wetland with a stream passing through it is a different problem than a small isolated depression.
Check state law. If the state has a wetland program with jurisdiction beyond the federal scope, factor in the state permit timeline even if the wetland is non-federal.
Check local ordinance. Some counties require setbacks from any wetland, jurisdictional or not.
If federal jurisdiction is possible, budget for a wetland delineation, a jurisdictional determination, and, if a permit is needed, the Section 404 process. Nationwide Permit 29 and Nationwide Permit 39 cover common development scenarios. Standard Individual Permits are the slowest path.
Red flags that should pause the deal
A Section 404 enforcement history on the parcel or adjacent parcels. The Corps does not forget.
An Approved JD on a nearby parcel that found jurisdiction. The map applies. The similar site implies similar law.
State-listed wetland species identified in proximity. Several states track this through natural heritage programs.
A parcel on the state stricter-than-federal list with any NWI polygon or hydric soil. The federal narrowing does not help.
The short version
Sackett narrowed the federal scope. It did not narrow state or local scope. NWI is a starting point, not an answer. The cheapest insurance on a parcel with any wetland indicator is a wetland scientist on the ground before the offer is written. That scientist's fee, typically four to eight thousand dollars for a small site, is the smallest number in the deal if the wetland is real.