Waters of the United States: Definition, Permits, and Penalties

Under the Clean Water Act, “waters of the United States” is the term that decides whether the federal government can regulate a stream, lake, wetland, or other water feature on a given piece of land. If a feature qualifies, discharging pollutants or placing fill into it requires a federal permit from the EPA or the U.S. Army Corps of Engineers. If it doesn’t qualify, federal law generally has nothing to say about it, though state law still might. The Supreme Court’s 2023 decision in Sackett v. EPA narrowed the definition significantly, particularly for wetlands, and a new proposed rule is working its way through the rulemaking process.

What Counts as Waters of the United States

The regulatory definition lives in 33 CFR 328.3 and covers several categories of water features.¹

Traditional navigable waters: rivers, lakes, and other bodies currently used, previously used, or potentially usable for interstate or foreign commerce, plus all waters subject to the ebb and flow of the tide.
The territorial seas, the belt of ocean extending three miles seaward from the coastline.²
Interstate waters that cross state boundaries, regardless of whether they carry boat traffic.
Impoundments of jurisdictional waters, including reservoirs and dammed sections.
Tributaries that carry relatively permanent, standing, or continuously flowing water into a jurisdictional water. A year-round creek that empties into a regulated river qualifies; a gully that runs only during heavy rain generally does not.
Wetlands adjacent to any of the above, if they meet the continuous surface connection test set by Sackett.

If a water feature doesn’t fit one of these categories, the Clean Water Act generally does not apply to it.

How Sackett Changed the Definition for Wetlands

The May 2023 decision in Sackett v. Environmental Protection Agency is the most consequential WOTUS ruling in a generation. Before Sackett, a wetland could be federally regulated if it had a “significant nexus” to navigable waters, meaning it significantly affected the chemical, physical, or biological integrity of a downstream water body. Agencies had wide discretion under that test, and wetlands connected to a river only through underground flow or seasonal flooding could still qualify.³

The Court rejected that approach. Writing for the majority, Justice Alito held that the Clean Water Act reaches only wetlands with a “continuous surface connection” to a relatively permanent body of water that is itself a water of the United States, so that it is “difficult to determine where the ‘water’ ends and the ‘wetland’ begins.”⁴ In practice, if you can see where the river or stream stops and the wetland starts because dry land or a berm sits between them, the wetland is probably outside federal reach. Subsurface connections like groundwater movement or soil saturation no longer establish jurisdiction.³

The EPA and Army Corps issued a conforming rule on September 8, 2023 that removed the significant nexus standard from the regulations.⁵

Estimates of how many wetlands lost federal protection vary widely. Under the narrowest reading of Sackett, roughly 19 million acres are affected. Under a broader reading, the number reaches 71 million acres, covering approximately 95 percent of individual wetlands nationwide. The real figure will emerge through years of jurisdictional determinations and litigation.

On November 17, 2025, the EPA and the Army announced a further proposed rule to clarify the definition and fully implement Sackett. Public comment closed on January 5, 2026, and the existing conforming rule remains in effect until a final rule takes its place.⁶

Features That Are Not Waters of the United States

The regulations explicitly exclude several categories, which matters most to farmers, developers, and rural landowners who might otherwise assume they need a federal permit.¹

Waste treatment systems, including treatment ponds and lagoons built to handle pollutants under the Clean Water Act.
Prior converted cropland: farmland drained or modified for crop production before December 23, 1985, as long as it stays in agricultural use.⁷
Ditches dug entirely in dry ground that don’t carry relatively permanent flow. A ditch excavated through a wetland is not excluded.
Artificially irrigated areas that would revert to dry ground if irrigation stopped.
Artificial ponds and lakes in dry land, including stock watering ponds, irrigation ponds, settling basins, and rice-growing impoundments.
Ornamental water features like reflecting pools and swimming pools.
Construction depressions, unless the work is abandoned and the resulting water body independently meets the WOTUS definition.
Swales, gullies, rills, and small washes with low-volume, infrequent, or short-duration flow.

A stock pond on a ranch or the drainage ditch along a driveway is not going to trigger a federal permitting requirement.

When You Need a Federal Permit

Two Clean Water Act programs generate almost all of the permitting obligations that landowners and businesses face.

Section 404: Dredge and Fill

If you plan to place dredge or fill material into a water of the United States, you need a Section 404 permit.⁸ “Fill material” is broader than it sounds. It includes soil, rock, sand, gravel, and anything used to raise the bottom elevation of a water body or replace it with dry land. Building a road across a wetland, constructing a levee along a stream, or grading land that extends into a creek bed all trigger the requirement.

Not every project needs a full individual permit. The Army Corps issues nationwide permits for categories of activities that cause only minimal adverse effects, functioning as pre-approvals when your project fits the conditions.⁹ Common nationwide permits carry acreage limits. For NWP 12 (utility lines) and NWP 14 (linear transportation projects), the threshold is generally a half-acre loss of non-tidal waters; exceed that limit or fail the general conditions and you need an individual permit, which involves case-by-case public interest review, environmental analysis, and a substantially longer timeline.¹⁰

When a permitted activity unavoidably destroys jurisdictional waters, the permit holder typically must offset the damage through compensatory mitigation.¹¹ The agencies prefer, in order: buying credits from an established mitigation bank, paying into an in-lieu fee program that funds future restoration, or doing permittee-responsible restoration on-site or elsewhere. Mitigation costs vary widely by region and wetland type, and they are one reason getting an accurate jurisdictional read before you plan a project can save real money.

Section 402: NPDES Discharge Permits

The National Pollutant Discharge Elimination System under Section 402 regulates discharges of pollutants from a “point source” into regulated waters.¹² The statute defines a point source as any identifiable conveyance, including pipes, ditches, channels, tunnels, and conduits.² A factory discharging wastewater through an outfall pipe, a municipal stormwater system, or a construction site releasing sediment-laden runoff through a ditch all fall within the program.

NPDES permits set specific limits on what pollutants you can release and in what quantities, and they require monitoring, record-keeping, and regular reporting. Most states administer the program under EPA authorization, so applications usually go to the state environmental agency.

Exemptions for Farming and Maintenance

Section 404(f) exempts several activities from the dredge-and-fill permit requirement, even in jurisdictional waters.⁸

Normal farming and ranching, including plowing, seeding, cultivating, minor drainage, and harvesting as part of an ongoing operation. If farmland has been idle long enough that you’d need to modify water flow to resume operations, the exemption no longer applies.
Emergency reconstruction and maintenance of currently serviceable dikes, dams, levees, bridge abutments, and similar structures, as long as the work doesn’t change the original design, size, or scope.¹³
Building or maintaining stock ponds, farm ponds, and irrigation ditches, and maintaining existing drainage ditches. Constructing new drainage ditches is not exempt.
Building or maintaining farm roads, forest roads, and temporary mining-equipment roads, as long as best management practices prevent impairment of water flow and minimize environmental damage.
Building temporary sedimentation basins on construction sites, provided you don’t place fill into the water itself.

The exemptions have a catch. If a nominally exempt activity is actually part of converting a water or wetland to a new use and reduces the reach or impairs the flow of jurisdictional waters, the exemption drops away. This “recapture” provision often trips up landowners whose activity technically qualifies but is really changing the character of the land.

How to Confirm Whether Your Property Has WOTUS

If you’re not sure whether your property contains waters of the United States, you can request a formal answer from the Army Corps of Engineers. There are two types of jurisdictional determinations, and the distinction matters.

A preliminary jurisdictional determination is advisory. It identifies potential jurisdictional features on your property but doesn’t legally bind the Corps. You can use it to move forward with a permit application, but it doesn’t protect you if the Corps later concludes the feature is actually jurisdictional. It also cannot be appealed.¹⁴

An approved jurisdictional determination is a written, legally binding decision stating whether specific wetlands or waterbodies on your property are or are not waters of the United States. An approved determination is valid for five years from the date of issuance, and you can file an administrative appeal under 33 CFR Part 331 if you disagree with it.¹⁵

You can submit either request through the Corps’ online Regulatory Request System, which auto-populates the required forms from the information you enter.¹⁶ Paper forms are also available (ENG 6247 for a jurisdictional determination, ENG 6249 for a preliminary determination). Aquatic resource delineation materials must be prepared separately. For any project involving significant investment, an approved jurisdictional determination up front is the only way to get a definitive answer about your obligations.

Penalties for Discharging Without a Permit

Discharging pollutants or fill into jurisdictional waters without the required permit carries both civil and criminal exposure, and the penalties escalate based on intent.¹⁷

Civil penalties can reach $25,000 per day per violation under the statutory text, adjusted upward for inflation. The EPA and the Corps can also issue compliance orders requiring you to stop the activity, restore the site, or both.

Criminal penalties come in two tiers. A negligent violation carries a fine of $2,500 to $25,000 per day and up to one year in prison, doubling to $50,000 per day and two years on a second conviction. A knowing violation carries a fine of $5,000 to $50,000 per day and up to three years in prison, rising to $100,000 per day and six years on a second conviction.¹⁸

The per-day structure is where most people underestimate their exposure. A developer who fills a wetland without a permit and continues work for 30 days doesn’t face one fine. The violation counts for each day the illegal discharge continues.

State Rules May Still Apply

Because Sackett removed federal protection from many wetlands, the practical rules for a given wetland now depend heavily on state law. Some states moved to fill the gap: Colorado passed legislation creating a state-level dredge-and-fill program covering waters defined more broadly than federal WOTUS, and California codified a “no net loss” wetland policy into state law. Other states moved the other way, with North Carolina narrowing its state definition of protected waters to match the post-Sackett federal definition and Indiana rolling back its isolated wetlands permitting program.¹⁹

The result is a patchwork. A wetland that lost federal protection after Sackett might still be heavily regulated in one state and completely unregulated in a neighboring state. If you are planning work near wetlands or waterbodies that appear to sit outside federal jurisdiction, check your state’s environmental regulations before you assume you can proceed without a permit.

1
eCFR. 33 CFR 328.3 – Definitions
2
Office of the Law Revision Counsel. 33 USC 1362 – Definitions
3
Congress.gov. Supreme Court Narrows Federal Jurisdiction Under Clean Water Act
4
Supreme Court of the United States. Sackett v Environmental Protection Agency
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US EPA. Revising the Definition of Waters of the United States
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US EPA. Waters of the United States
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US EPA. CWA Section 404 and Swampbuster Wetlands on Agricultural Lands
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Office of the Law Revision Counsel. 33 USC 1344 – Permits for Dredged or Fill Material
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U.S. Army Corps of Engineers. Permit Types
10
Federal Register. Reissuance and Modification of Nationwide Permits
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U.S. Environmental Protection Agency. Background about Compensatory Mitigation Requirements under CWA Section 404
12
Office of the Law Revision Counsel. 33 USC 1342 – National Pollutant Discharge Elimination System
13
U.S. Army Corps of Engineers. Section 404 Exemptions
14
US Army Corps of Engineers. Administrative Appeal Process 33 CFR Part 331
15
U.S. Army Corps of Engineers. Jurisdictional Determination Process
16
U.S. Army Corps of Engineers. Regulatory Program Forms
17
Office of the Law Revision Counsel. 33 USC 1319 – Enforcement
18
Office of the Law Revision Counsel. 33 USC 1319 – Enforcement
19
Environmental Law Institute. Navigating Newly Non-WOTUS Wetlands a Study of Six States Wetlands Programs after Sackett v EPA