Obama Administration Issues Final Rule on “Waters of the United States” – The Rule Will Expand The Universe Of “Waters” Subject To Federal Regulation


  • The U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency have issued a final rule revising the definition of “Waters of the United States” under the Clean Water Act that will impact many segments of the U.S. economy.
  • The final rule’s expansive definition of “tributary” and the categorical inclusion of adjacent waters and wetlands within the 100-year floodplain of a tributary will make it easier for the agencies to regulate large areas of the landscape without the need for site specific evidence demonstrating a significant nexus to a navigable water.
  • The final rule could also sweep in isolated features, such as vernal pools and prairie potholes, located a great distance from navigable waters, particularly impacting the arid West.

On May 27, 2015, the U.S. Army Corps of Engineers (Corps) and the U.S. Environmental Protection Agency (EPA) (collectively, the “agencies”) issued a final rule revising the regulatory definition of “Waters of the United States” under the federal Clean Water Act (CWA).1 The rule, which replaces guidance issued by the Bush administration in 2007 and 2008, responds to the confusion in the wake of the 2006 Supreme Court opinion in Rapanos v. United States2 and represents the most expansive interpretation of CWA jurisdiction since the law was enacted in 1972. The agencies’ implementation of this rule will be felt throughout the United States, particularly in the arid and semi-arid western states, such as California. EPA and the Corps maintain that the new rule is narrower than under the existing regulation, an assertion strongly disputed by the regulated community.3 At the same time, the agencies also estimate that the rule will increase the regulated waters by 3 percent and increase the cost to regulated entities and governments $162 million – $279 million per year, largely through increased permitting costs. While the agencies claim that the rule provides more clarity as to the limits of the CWA, there will be a great deal of uncertainty in its actual implementation. Due to vehement opposition from industry groups, there is one certainty: there will be litigation in the future.

Defining “Waters” Regulated by the Corps and EPA Highly Controversial

The CWA gives the Corps and EPA jurisdiction to regulate all “navigable waters,” which the law defines only as all “Waters of the United States.”4 Understanding what constitutes the “Waters of the United States” is critical because it defines the scope of a host of regulatory programs that compel landowners to seek permits from the federal government before undertaking various activities on their land – specifically, programs under the following CWA sections:

  • 311: oil spill program
  • 401: water quality certification
  • 402: NPDES discharge program
  • 404: dredged or fill material discharge permit program

The final rule provides a revised definition of “Waters of the United States” and culminates more than eight years of inconsistent administrative responses to an uncertain state of the law. A pair of Supreme Court cases, Solid Waste Agency of Northern Cook Cty. v. Army Corps of Engineers,5 and Rapanos v. Army Corps of Engineers6 provided unclear guidance about how broadly the federal government could regulate waters which have no surface connection to traditional “navigable” waterways. In a pivotal concurring opinion in Rapanos, Justice Anthony Kennedy opined that waters have a sufficient “nexus” to traditional navigable waters to enable regulation if the waters, “either alone or in combination with similarly situated lands in the region, significantly affect the chemical, physical, and biological integrity of other covered waters more readily understood as ‘navigable.’”7 Since four other justices understood the federal government’s jurisdiction to reach even further, Justice Kennedy’s opinion has been understood to be the “least common denominator” establishing the necessary requirements for federal jurisdiction. The final rule attempts to establish which types of waters do, or could, have the kind of “nexus” described in Justice Kennedy’s opinion.

The agencies’ 2014 proposed rule was highly controversial and elicited over one million comments from a huge range of stakeholders, including public agencies, state and local governments, industry, mining, agriculture and other business interests. While the agencies have made some important changes to provide clearer guidance of what waters will be regulated, the final rule still sanctions broad federal regulation over vast areas of the American landscape and also leaves areas of major uncertainty. The final rule will take effect 60 days from the date it is officially published in the Federal Register.

Categories of “Waters of the United States”

The final rule replaces the prior regulatory definition of “Waters of the United States” with eight categories of waters.

The first three categories are jurisdictional by rule and remain unchanged from the prior definition:

1. Traditional Navigable Waters. This applies to all waters currently used, used in the past or that may be susceptible to use in interstate or foreign commerce, including tidal waters (e.g., Mississippi River or Los Angeles River).

2. Interstate Waters. This applies toall interstate waters, including interstate wetlands (e.g., Colorado River).

3. Territorial Seas. This applies to coastal waters up to three miles from the shore.

The next three categories are also now jurisdictional by rule and have been modified from the proposed rule:

4. Impoundments. The proposed rule only included impoundments of waters (1)-(3) above. The final rule includes all impoundments “of waters otherwise identified as waters of the United States under this section,” and so it also includes impoundments of tributaries, adjacent waters and “nexus” waters (waters (5)-(8) below).

5. Covered Tributaries. This applies to all “tributaries” of waters (1)-(3) above. The rule defines a tributary as a water that is “characterized by the presence of the physical indicators of a bed and banks and an ordinary high water mark” which could cover largely dry areas miles away from a traditional navigable water.

6. Adjacent Waters. The rule categorically includes all waters, not just wetlands, adjacent to tributaries, and defines “adjacent” as “bordering, contiguous and neighboring.” Such adjacent waters would include:

  • waters separated from a tributary by a barrier such as a “constructed, dike or barrier, natural river berms, beach dunes and the like”
  • waters located within the 100 year floodplain and not more than 1500 feet from the ordinary high water mark of the tributary
  • waters for which any portion is within 1,500 feet from the high tide line of a traditionally navigable water, interstate water or the territorial sea or within 1,500 feet of the ordinary high water mark of the Great Lakes

The final two categories are subject to case-specific analysis to determine whether they are jurisdictional:

7. Listed Significant Nexus Waters. The rule lists five categories of waters that are subject to a case-specific “significant nexus” analysis unless they are considered adjacent waters and would then be categorically jurisdictional. These include prairie potholes, Carolina and Delmarva Bays, pocosins, western vernal pools and Texas coastal prairie wetlands. In conducting a case-specific analysis, the rule finds that these listed waters are “similarly situated“ and must be combined in a case-specific significant nexus analysis.

8. Other Significant Nexus Waters. Non-adjacent waters, such as wetlands, ponds, impoundments or certain non-exempt waters in which normal farming, ranching and silvicultural activities occur, that are located within the 100-year floodplain of or within 4,000 feet of the high tide line of waters listed in (1)-(5) are also subject to a case-specific “significant nexus” analysis in which other “similarly situated” waters must be identified, then analyzed in aggregate to determine if the group of waters within a point of entry for the watershed for their effect on the chemical, physical, or biological integrity of waters listed in (1)-(3).

New “Significant Nexus” Test

The final rule defines the term “significant nexus” to mean a significant effect on the chemical, physical, or biological integrity of a traditional navigable water, interstate water, or the territorial seas. A “significant” contribution is any effect that is “more than speculative or insubstantial.” In this analysis, waters are evaluated with similarly situated waters based on an assessment of the functions they perform. The following functions are considered:

  1. sediment trapping
  2. nutrient recycling
  3. pollutant filtering
  4. flood water retention
  5. runoff storage
  6. flow contribution
  7. organic matter export
  8. food resource export
  9. essential aquatic habitat

If the agencies find that any one of these functions has a significant effect, either alone or together with similarly situated waters in the region, then the significant nexus may be established. This is a broad standard that gives substantial discretion to the agencies in making jurisdictional determinations. The agencies cite extensively to EPA’s “connectivity study,” a synthesis of published studies largely supported by an EPA Science Advisory Board (SAB) panel to support its significant nexus analysis.

Exclusions to the Definition of “Waters of the United States”

The final rule provides a list of exclusions to the definition of “Waters of the United States” that represents a compilation of exclusions based on the prior regulation and past practice.

The exclusions that carry over from the current regulations include:

  • CWA section 404(f) exemption for normal farming activities
  • waste treatment systems
  • prior converted cropland

The exclusions regularly applied in practice include:

  • artificially irrigated areas on dry land
  • artificial lakes and ponds created on dry land
  • artificial reflecting pools, swimming pools and ornamental waters created on dry land
  • water-filled depressions/pits incidental to mining or construction
  • certain ditches, including those (i) with ephemeral flow that are not a relocated tributary or excavated in a tributary; (ii) with intermittent flow that are not a relocated tributary or excavated in a tributary; and (iii) ditches that do not flow, either directly or through another jurisdictional water
  • groundwater
  • erosional features, including gullies, rills and other ephemeral features that do not meet the definition of a tributary
  • puddles
  • stormwater control features created on dry land
  • waste water recycling structures constructed in dry land; detention/retention basins for wastewater recycling; groundwater recharge basins; percolation ponds and water distributary structures of wastewater recycling

Implications of the Final Rule

The broad definition of tributaries greatly increases the reach of the final rule. For the first time, the rule defines “tributaries” and includes all tributaries and their “adjacent waters” as “jurisdictional by rule.” The preamble asserts the new definition of tributary adds qualifications that were not previously in place, and suggests this would narrow the scope of regulatory coverage; however, the broad definition suggests otherwise. The definition of tributary includes all waters (natural or man-made that are not otherwise excluded) that flow to a traditional navigable water, interstate water or the territorial seas and that have an ordinary high water mark or a bed or bank, even where the feature is broken up by a road, a wetland or other barrier. No actual flow to a jurisdictional water need be documented, and the connection to a jurisdictional water can be broken up, so there remains a significant amount of discretion in the agencies to determine what is a tributary. Impoundments are also now defined as including impoundments of tributary water. Further, the rule defines “neighboring” adjacent waters as jurisdictional by rule if they are within 1,500 feet of that tributary or within the 100-year floodplain of the tributary. Additionally, non-adjacent waters within 4,000 feet of a tributary are also subject to a significant nexus test. Thus, contrary to the agencies’ claim, the definition can be read extremely broadly, may not actually reflect a significant nexus to jurisdictional waters, and – when combined with the new definition of impoundments, adjacent waters and other significant nexus waters – could greatly expand the reach of the CWA. This is particularly significant in the arid West, where historical water features that no longer flow could get swept in, the “connection” to a traditional navigable water could be remote and interrupted, and all waters within 4,000 feet of that tributary need to be examined.

Agency use of desktop analyses in making a variety of determinations under the rule can result in inaccurate determinations. The rule sanctions agency use of “desktop” information such as watershed studies, U.S. Geological Survey maps, aerial photography or other remote sensing information to determine whether a water is a tributary, whether there is a connection to a jurisdictional water, and what waters are “adjacent” to that tributary.The rule also allows use of FEMA maps, which are not always up to date, to determine floodplain information. Use of desktop information can result in jurisdictional determinations that do not accurately reflect conditions on the ground and will be very difficult for landowners to challenge.

The rule’s exclusions may not apply because they include many exceptions. While the agencies claim the exclusions help narrow federal jurisdiction, there are, in many cases, exceptions or restrictions to the exclusions that limit their utility. For example, limiting the rule’s exclusion to features created on dry land, even where such structures or features were constructed based on a CWA Section 404 fill permit, and expressly regulating ditches constructed in a “relocated tributary” means that many such features will become regulated. This could potentially sweep in roadside and other ditches with little or no connection to a navigable water. Limiting the exclusion of stormwater control features and wastewater recycling structures to those features or structures created on dry land means that the agencies would retain jurisdiction over any such features even if they were created based on a fill permit; this could continue to present maintenance issues raised by local agency commenters. Also, because the rule does not define excluded “puddles” and “erosional features,” it will be hard to distinguish such features from covered ephemeral tributaries in many cases. Further, as noted in the new rule, while the waters listed in the exclusions are not “Waters of the United States,” they can serve as a hydrologic connection that the agencies would consider under a case-specific significant nexus.

Lack of complete grandfathering could result in a significant amount of new work for certain projects. The final rule states that the agencies do not intend to reopen existing jurisdictional determinations (JDs) and such JDs for issued permits and authorizations will remain valid until the expiration date of the permit or authorization. However, this grandfathering provision does not cover pending JD requests.. Applications run the risk of having the new rule retroactively applied to pending JD requests or new permit applications with a pending JD even where the applicant has spent considerable time and money in submitting the JD application and seeking approval.

An Uncertain Future for the Final Rule

The final rule will almost certainly be challenged by industry as, among other things, deviating from the Rapanos “significant nexus” standard articulated by Justice Kennedy by sweeping in many ephemeral and isolated waters and wetlands that have only a remote, if any, actual connection to traditionally navigable waters. Additionally, Congress will continue its legislative efforts to reverse and repeal the rule.8 Given the inherent uncertainty and ambiguity in the rule, EPA and the Corps will likely need to develop and issue detailed implementation guidance. Meanwhile, the regulators and the regulated community will need to grapple with actually applying the rule 60 days after it is published. Regardless of what happens next, one thing is certain: the controversy surrounding the rule will not subside any time soon.



1 As of June 4, 2015, the final CWA is available in its “prepublication” form (last accessed June 4, 2015). It will later be published in the Federal Register, at which point the new definition will be codified in federal regulations at Department of the Army, Corps of Engineers, 33 CFR Part 328 and EPA 40 CFR Parts 110, 112, 116, 117, 122, 230, 232, 300, 302 and 401.

2 547 U.S. 715 (2006).

3 Prepublication rule at p. 10. See also “Barack Obama’s water war,” Politico, May 28, 2015.

4 33 U.S.C. 502 (7).

5 531 U.S. 159 (2001) (SWANCC).

6 547 U.S. 715 (2006).

7Id. at 780.

8 On May 12, 2015, the House passed H.R. 1732 that would require the agencies to withdraw the rule and engage in further consultations. The bill was sponsored by Rep. Shuster (R-Pa.) and passed with the votes of 237 Republicans and 24 Democrats.