Navigable waters

Scope

The definition of “navigable waters” and “waters of the United States” helps regulators, regulated entities, and the public understand where the CWA and its implementing regulations apply and where they do not. See the list of implementing regulations in the Regulatory Citations section below.

Regulatory citations

• 33 CFR 328 — Definition of waters of the United States
• 40 CFR 110 — Discharge of oil
• 40 CFR 112 — Oil pollution prevention
• 40 CFR 116 — Designation of hazardous substances
• 40 CFR 117 — Determination of reportable quantities for hazardous substances
• 40 CFR 120 — Definition of waters of the United States
• 40 CFR 122 — EPA administered permit programs: The national pollutant discharge elimination system
• 40 CFR 230 — Section 404(b)(1) guidelines for specification of disposal sites for dredged or fill material
• 40 CFR 232 — 404 programs definitions: Exempt activities not requiring 404 permits
• 40 CFR 300 — National oil and hazardous substances pollution contingency plan
• 40 CFR 302 — Designation, reportable quantities, and notification
• 40 CFR 401 — General provisions

Key definitions

• Adjacent wetlands: Wetlands that: (A) Abut, meaning to touch at least at one point or side of, a water identified in 120.2(1)(i), (ii), or (iii); (B) Are inundated by flooding from a water identified in 120.2(1)(i), (ii), or (iii) in a typical year; (C) Are physically separated from a water identified in 120.2(1)(i), (ii), or (iii) only by a natural berm, bank, dune, or similar natural feature; or (D) Are physically separated from a water identified in 120.2(1)(i), (ii), or (iii) of this definition only by an artificial dike, barrier, or similar artificial structure so long as that structure allows for a direct hydrologic surface connection between the wetlands and the water identified in 120.2(1)(i), (ii), or (iii) in a typical year, such as through a culvert, flood or tide gate, pump, or similar artificial feature. An adjacent wetland is jurisdictional in its entirety when a road or similar artificial structure divides the wetland, as long as the structure allows for a direct hydrologic surface connection through or over that structure in a typical year.
• Ditch: A constructed or excavated channel used to convey water.
• Ephemeral: Surface water flowing or pooling only in direct response to precipitation (e.g., rain or snow fall).
• High tide line: The line of intersection of the land with the water’s surface at the maximum height reached by a rising tide. The high tide line may be determined, in the absence of actual data, by a line of oil or scum along shore objects, a more or less continuous deposit of fine shell or debris on the foreshore or berm, other physical markings or characteristics, vegetation lines, tidal gages, or other suitable means that delineate the general height reached by a rising tide. The line encompasses spring high tides and other high tides that occur with periodic frequency but does not include storm surges in which there is a departure from the normal or predicted reach of the tide due to the piling up of water against a coast by strong winds, such as those accompanying a hurricane or other intense storm.
• Intermittent: Surface water flowing continuously during certain times of the year and more than in direct response to precipitation (e.g., seasonally when the groundwater table is elevated or when snowpack melts).
• Lakes and ponds, and impoundments of jurisdictional waters: Standing bodies of open water that contribute surface water flow to a water identified in 120.2(1)(i) in a typical year either directly or through one or more waters identified in 120.2(1)(ii), (iii), or (iv). A lake, pond, or impoundment of a jurisdictional water does not lose its jurisdictional status if it contributes surface water flow to a downstream jurisdictional water in a typical year through a channelized non-jurisdictional surface water feature, through a culvert, dike, spillway, or similar artificial feature, or through a debris pile, boulder field, or similar natural feature. A lake or pond, or impoundment of a jurisdictional water is also jurisdictional if it is inundated by flooding from a water identified in 120.2(1)(i), (ii), or (iii) in a typical year.
• Navigable waters: “Waters of the United States,” including the territorial seas.
• Ordinary high water mark: That line on the shore established by the fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding areas.
• Perennial: Surface water flowing continuously year-round.
• Prior converted cropland: Any area that, prior to December 23, 1985, was drained or otherwise manipulated for the purpose, or having the effect, of making production of an agricultural product possible. EPA and the Corps will recognize designations of prior converted cropland made by the Secretary of Agriculture. An area is no longer considered prior converted cropland for purposes of the Clean Water Act when the area is abandoned and has reverted to wetlands, as defined in 120.2(3)(xvi). Abandonment occurs when prior converted cropland is not used for, or in support of, agricultural purposes at least once in the immediately preceding five years. For the purposes of the Clean Water Act, the EPA Administrator shall have the final authority to determine whether prior converted cropland has been abandoned.
• Snowpack: Layers of snow that accumulate over extended periods of time in certain geographic regions or at high elevation (e.g., in northern climes or mountainous regions).
• Tidal waters and waters subject to the ebb and flow of the tide: Those waters that rise and fall in a predictable and measurable rhythm or cycle due to the gravitational pulls of the moon and sun. Tidal waters and waters subject to the ebb and flow of the tide end where the rise and fall of the water surface can no longer be practically measured in a predictable rhythm due to masking by hydrologic, wind, or other effects.
• Tributary: A river, stream, or similar naturally occurring surface water channel that contributes surface water flow to a water identified in 120.2(1)(i) in a typical year either directly or through one or more waters identified in 120.2(1)(ii), (iii), or (iv). A tributary must be perennial or intermittent in a typical year. The alteration or relocation of a tributary does not modify its jurisdictional status as long as it continues to satisfy the flow conditions of this definition. A tributary does not lose its jurisdictional status if it contributes surface water flow to a downstream jurisdictional water in a typical year through a channelized non-jurisdictional surface water feature, through a subterranean river, through a culvert, dam, tunnel, or similar artificial feature, or through a debris pile, boulder field, or similar natural feature. The term tributary includes a ditch that either relocates a tributary, is constructed in a tributary, or is constructed in an adjacent wetland as long as the ditch satisfies the flow conditions of this definition.
• Typical year: When precipitation and other climatic variables are within the normal periodic range (e.g., seasonally, annually) for the geographic area of the applicable aquatic resource based on a rolling thirty-year period.
• Upland: Any land area that under normal circumstances does not satisfy all three wetland factors (i.e., hydrology, hydrophytic vegetation, hydric soils) identified in 120.2(3)(xvi), and does not lie below the ordinary high water mark or the high tide line of a jurisdictional water.
• Waste treatment system: Includes all components, including lagoons and treatment ponds (such as settling or cooling ponds), designed to either convey or retain, concentrate, settle, reduce, or remove pollutants, either actively or passively, from wastewater prior to discharge (or eliminating any such discharge).
• Waters of the United States:
  1. Jurisdictional waters. For purposes of the Clean Water Act, 33 U.S.C. 1251 et seq. and its implementing regulations, subject to the exclusions in paragraph (2) below, the term “waters of the United States” means:
     1. The territorial seas, and waters which are currently used, or were used in the past, or may be susceptible to use in interstate or foreign commerce, including waters which are subject to the ebb and flow of the tide;
     2. Tributaries;
     3. Lakes and ponds, and impoundments of jurisdictional waters; and
     4. Adjacent wetlands.
  2. Non-jurisdictional waters. The following are not “waters of the United States”:
     1. Waters or water features that are not identified in paragraph (1)(i), (ii), (iii), or (iv) of this definition;
     2. Groundwater, including groundwater drained through subsurface drainage systems;
     3. Ephemeral features, including ephemeral streams, swales, gullies, rills, and pools;
     4. Diffuse stormwater run-off and directional sheet flow over upland;
     5. Ditches that are not waters identified in paragraph (1)(i) or (ii) of this definition, and those portions of ditches constructed in waters identified in paragraph (1)(iv) of this definition that do not satisfy the conditions of 120.2(3)(i);
     6. Prior converted cropland;
     7. Artificially irrigated areas, including fields flooded for agricultural production, that would revert to upland should application of irrigation water to that area cease;
     8. Artificial lakes and ponds, including water storage reservoirs and farm, irrigation, stock watering, and log cleaning ponds, constructed or excavated in upland or in non-jurisdictional waters, so long as those artificial lakes and ponds are not impoundments of jurisdictional waters that meet the conditions of 120.2(3)(vi);
     9. Water-filled depressions constructed or excavated in upland or in non-jurisdictional waters incidental to mining or construction activity, and pits excavated in upland or in non-jurisdictional waters for the purpose of obtaining fill, sand, or gravel;
     10. Stormwater control features constructed or excavated in upland or in non-jurisdictional waters to convey, treat, infiltrate, or store stormwater runoff;
     11. Groundwater recharge, water reuse, and wastewater recycling structures, including detention, retention, and infiltration basins and ponds, constructed or excavated in upland or in non-jurisdictional waters; and
     12. Waste treatment systems.
• Wetlands: Areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.

Summary of requirements