Under the Clean Water Act, waters of the United States are the water bodies and wetlands subject to federal regulation: traditional navigable waters, the territorial seas, interstate waters, impoundments of those waters, tributaries that carry relatively permanent flow, and wetlands with a continuous surface connection to one of them. Everything else, including many isolated wetlands, ephemeral streams, and most agricultural features, sits outside federal jurisdiction. The Supreme Court’s 2023 decision in Sackett v. EPA narrowed this definition significantly, and knowing where your property falls determines whether you need a federal permit before you dig, fill, or discharge.
What Counts as a Water of the United States
Federal jurisdiction rests on three foundational categories. Traditional navigable waters come first: rivers, lakes, and other water bodies currently used, historically used, or susceptible to use in interstate or foreign commerce, along with all waters subject to tidal influence. The territorial seas, extending outward from the coastline, are the second category. Interstate waters, meaning waters that cross state boundaries, complete the primary list.1eCFR. 33 CFR 328.3 – Definitions
Impoundments of jurisdictional waters keep their federal status. A reservoir formed by damming a navigable river remains regulated because the underlying water was regulated before the dam existed.
Tributaries and the Relatively Permanent Standard
A tributary is jurisdictional only if it carries relatively permanent flow and connects to a downstream navigable water. “Relatively permanent” means water that stands or flows continuously year-round, or at least throughout the wet season. The channel must also have a defined bed and banks.2Federal Register. Updated Definition of Waters of the United States
The connection itself has to be continuous surface flow. If a tributary reaches the downstream jurisdictional water only through culverts, tunnels, debris piles, or other features that don’t themselves convey relatively permanent flow, that connection is severed and jurisdiction does not extend upstream.2Federal Register. Updated Definition of Waters of the United States
When a Wetland Is Federally Regulated
The Supreme Court reshaped wetland jurisdiction in Sackett v. EPA (2023). The Clean Water Act now covers only wetlands with a “continuous surface connection” to a relatively permanent water body that itself qualifies as a Water of the United States. The wetland must be practically indistinguishable from that jurisdictional water, meaning it’s difficult to tell where the water ends and the wetland begins.3Supreme Court of the United States. Sackett v. EPA
This is a real departure from the older approach. Before Sackett, agencies could reach wetlands with only a hydrological connection, including subsurface water links or seasonal flooding. That is gone. Physical, visible, surface-level contact between the wetland and the jurisdictional water is what the law now requires. If a road, berm, levee, or similar barrier separates a wetland from the nearest regulated water body, the wetland likely falls outside federal jurisdiction.3Supreme Court of the United States. Sackett v. EPA
The analysis runs in two steps. First, confirm the adjacent water body is itself a Water of the United States, meaning a relatively permanent body connected to traditional navigable waters. Second, show the wetland has a continuous surface connection making it effectively part of that same body. Both must be present.
Wetland identification uses a three-parameter test: hydrophytic vegetation (plants adapted to saturated soils), hydric soils, and evidence of wetland hydrology. All three markers typically need to be present for an area to be delineated as a wetland in the first place.4U.S. Army Corps of Engineers. Delineating Waters of the United States Including Wetlands
What Is Not a Water of the United States
Several categories of water features fall outside federal jurisdiction. These exclusions cover land types property owners commonly deal with, so knowing them can save an unnecessary permit process.
Ephemeral Streams and Dry Washes
Waterways that carry flow only in direct response to rainfall or snowmelt are not jurisdictional. These ephemeral features, common in arid regions, do not meet the relatively permanent standard. A desert wash that runs for a few hours after a storm is not a Water of the United States, even if it eventually connects to a river miles downstream.3Supreme Court of the United States. Sackett v. EPA
Groundwater
Groundwater has never been treated as jurisdictional, and agencies have proposed formally codifying that exclusion. It includes groundwater drained through subsurface drainage systems. Once groundwater surfaces and becomes baseflow in a relatively permanent stream, that surface expression can be jurisdictional, but the groundwater itself is not.2Federal Register. Updated Definition of Waters of the United States
Agricultural and Artificial Features
The regulations explicitly exclude several categories of man-made or agricultural water features:
- Prior converted cropland designated by the Secretary of Agriculture, though the exclusion ends if the land is no longer used for crop production.
- Waste treatment systems, including ponds and lagoons designed to comply with Clean Water Act requirements.
- Areas watered by artificial irrigation that would revert to dry land without it.
- Ditches excavated in upland areas that do not carry relatively permanent flow.
- Artificial lakes or ponds created by digging in dry land for purposes like stock watering or irrigation.
How to Find Out If Your Property Is Jurisdictional
Before developing property near water features, most owners want a formal answer on federal jurisdiction. The Army Corps of Engineers issues two types of jurisdictional determinations, and the choice between them matters.
A Preliminary Jurisdictional Determination (PJD) is a non-binding advisory that treats every aquatic feature on the property as potentially jurisdictional for permit processing. It’s faster, but by accepting a permit based on a PJD, you agree that every aquatic resource on the site will be treated as jurisdictional and you waive any future challenge in enforcement actions, administrative appeals, or federal court.5U.S. Army Corps of Engineers. Regulatory Guidance Letter 16-01 – Jurisdictional Determinations
An Approved Jurisdictional Determination (AJD) is legally binding. It identifies which aquatic resources on a parcel are jurisdictional and maps their geographic limits. An AJD remains valid for five years and can be administratively appealed. Using an AJD can also reduce required compensatory mitigation, because only confirmed jurisdictional resources count toward impact calculations.5U.S. Army Corps of Engineers. Regulatory Guidance Letter 16-01 – Jurisdictional Determinations
If you’re confident the site has jurisdictional features and want to move quickly, a PJD is efficient. If you believe some or all features on the property are non-jurisdictional, an AJD gives you a binding determination you can rely on and challenge if needed.
The request goes to your local Army Corps district office with a data package: site maps, topographic surveys, soil samples, vegetation surveys, property coordinates, boundary descriptions, and identification of any water features present. A field officer may visit the property to verify the data. Most applicants hire environmental consultants to prepare the submission, and professional wetland delineation typically costs several thousand dollars or more depending on acreage and complexity.
What Happens If You Discharge Without a Permit
Any discharge of dredged or fill material into a Water of the United States requires a permit under Section 404 of the Clean Water Act.6U.S. Environmental Protection Agency. Permit Program under CWA Section 404 Skipping that step is expensive. Civil penalties can reach $68,446 per day per violation after the most recent inflation adjustment.7Federal Register. Civil Monetary Penalty Inflation Adjustment Rule
Criminal exposure depends on culpability. Negligent violations bring fines of $2,500 to $25,000 per day and up to one year in prison, with a second conviction doubling the maximum fine and extending imprisonment to two years. Knowing violations carry fines of $5,000 to $50,000 per day and up to three years in prison.8U.S. Environmental Protection Agency. Clean Water Act Section 309 Federal Enforcement Authority
The Clean Water Act sets no enforcement deadline of its own. Federal courts generally apply the five-year period in 28 U.S.C. ยง 2462 to civil penalty actions, running from when the violation first occurred.9Office of the Law Revision Counsel. 28 USC 2462 – Time for Commencing Proceedings Ongoing violations, such as a permanent fill that was never removed, can reset that clock, so old unpermitted work is not automatically safe.
Appealing a Jurisdictional Determination
If you disagree with an Approved Jurisdictional Determination, the deadline to appeal is strict. You must submit a Request for Appeal to the appropriate Corps division office within 60 days of the date on the Notification of Appeal Process fact sheet. Miss the window and the determination stands with no administrative remedy.10eCFR. 33 CFR Part 331 – Administrative Appeal Process
The Request for Appeal must include your name, the Corps file number, specific reasons for the appeal, any supporting data already in the record, and a grant of right of entry allowing a review officer to access the site. You cannot submit new information with the appeal itself. If you have new data, you send it to the district engineer within the 60-day window for reconsideration, which is a separate process.10eCFR. 33 CFR Part 331 – Administrative Appeal Process
Simple disagreement isn’t a basis for appeal. You have to identify a specific deficiency:
- A procedural error, meaning the Corps failed to follow a required step.
- Incorrect application of law or policy, meaning the determination misapplied a regulation or official guidance.
- Omission of a material fact from the record.
- Use of incorrect data.
- Incorrect application of the wetland delineation criteria.
You have to exhaust the administrative appeal before filing in federal court. Skipping straight to litigation will get the case dismissed.10eCFR. 33 CFR Part 331 – Administrative Appeal Process