Controversial New Clean Water Rule Unlikely to Significantly Change Regulatory Status Quo

Legal Alert

On May 27, EPA and the U.S. Army Corps of Engineers jointly issued their long-expected and much-debated rule defining which waters are protected by the federal Clean Water Act (CWA).[1]  In announcing the rule, President Obama said that it is needed because “[o]ne in three Americans now gets drinking water from streams lacking clear protection.”[2]  The executive director of an environmental advocacy group described the rule as “the biggest victory for clean water in a decade.”[3]  On the other hand, industry and agricultural trade associations vehemently oppose the rule, and U.S. House of Representatives Speaker John Boehner called it “a raw and tyrannical power grab that will crush jobs.”[4]  Indeed, the House just two weeks ago passed the latest in a series of bills that would require EPA and the Corps to withdraw the rule—albeit without a veto-proof majority.[5]

Given the uproar surrounding the rule, one would expect that it would result in more extensive or stringent regulations and perhaps even cleaner water.  But for almost all entities and waterbodies, the rule is unlikely to change the regulatory status quo, although it could in some circumstances make enforcement actions easier.  Notwithstanding the rhetoric about restoring protection to streams and job-killing tyrannical power grabs, the reason that business group oppose the rule and environmental advocacy groups support it is that it does not substantially reduce the very broad scope of waters that EPA and the Corps currently protect and have historically protected under the CWA.  Business groups are already preparing legal challenges to the rule, which will almost certainly reach the U.S. Supreme Court.  If those challenges are successful, many smaller waterbodies and wetlands might no longer be protected by the CWA.  But in the meantime, the rule will not change the extent to which most entities and waterbodies are regulated. We discuss the reasons for this below.


At the heart of the CWA is its prohibition against discharging pollutants to “navigable waters” without a permit.[6]  Thus, only “navigable waters” are protected by the CWA.  The CWA defines “navigable waters” as “waters of the United States” (WOTUS),[7] but it does not define WOTUS.  Soon after the CWA was enacted in 1972, EPA adopted a rule that defined WOTUS broadly to include most surface waters, regardless of navigability,[8] while the Corps defined WOTUS much more narrowly as waters that are, were, or could be actually navigable (so-called “traditionally navigable waters”).[9]  In 1975, a federal court invalidated the Corps’ definition, holding that it was too narrow because Congress, by defining “navigable waters” as WOTUS, had not intended to limit the waters protected by the CWA to traditionally navigable waters.[10]  In response, the Corps adopted a definition similar to EPA’s.  Following a few further revisions, the agency definitions of WOTUS have remained essentially unchanged since 1986.[11]

The current definitions of WOTUS, which remain in effect until the new rule announced on May 27 takes effect, include the following waterbodies:

  • all traditionally navigable waters;
  • all “interstate waters”;
  • the “territorial sea” (the sea within 3 nautical miles of shore);
  • all “other waters such as intrastate lakes, rivers, streams (including intermittent streams), mudflats, sandflats, ‘wetlands,’ sloughs, wet meadows, playa lakes, or natural ponds the use, degradation, or destruction of which would affect or could affect interstate or foreign commerce”;
  • all “[t]ributaries” of WOTUS; and
  • all wetlands “adjacent” to WOTUS.[12]

These are very broad categories that, at least potentially, encompass all surface waters.  Not only do they include all traditionally navigable waters and interstate waters, but also all waters whose use, degradation, or destruction “would affect or could affect” interstate or foreign commerce.  Because courts have held that even relatively minor and seemingly local actions may affect interstate or foreign commerce,[13] this last category could include, for example, any water that is visited or that could be visited by an interstate traveler for recreation, such as birdwatching.  Moreover, the categories in the currently effective rule include all tributaries (direct or indirect) and all impoundments of any of these waters (including impoundments of tributaries), as well as wetlands adjacent to any of these waters.

But in cases decided in 2001 and 2006, the U.S. Supreme Court held that the Corps had applied the statutory term WOTUS too expansively.[14]  The Court did not invalidate any portion of the Corps’ WOTUS definition, and no member of the Court argued that WOTUS is limited to traditionally navigable waters.  In each case, however, a five-member majority of the Court reasoned that Congress’ use of the term “navigable waters” requires that waters protected by the CWA must either be traditionally navigable waters or have some substantial relationship to traditionally navigable waters, although the majority could not agree on what that relationship must be.

In the most recent decision, Rapanos v. United States, a plurality of four of the nine justices concluded that WOTUS includes only traditionally navigable waters, “relatively permanent” bodies of water that are “connected to” traditionally navigable waters, and wetlands that have a “continuous surface connection” to these waters.[15]  A fifth justice, Justice Kennedy, argued that any water with a “significant nexus” to a traditionally navigable water is also a WOTUS, regardless whether it is “relatively permanent” or has a continuous surface connection to a traditionally navigable water.  By “significant nexus,” he meant that the water “either alone or in combination with similarly situated [waters] in the region significantly affect[s] the chemical, physical, and biological integrity of other covered waters more readily understood as ‘navigable.’”[16]  Because the four dissenting justices would have agreed that any waterbody that satisfies either the plurality’s narrower standard or Justice Kennedy’s generally broader standard is a WOTUS,[17] a majority of five justices would agree that at least any waterbody with a “significant nexus” is a WOTUS.  Accordingly, Justice Kennedy’s “significant nexus” standard has generally become the controlling standard for determining WOTUS.[18]

In practice, the Corps’ and EPA’s application of the nebulous “significant nexus” standard since Rapanos has not resulted in a substantial contraction of the scope of WOTUS, and the lower federal courts have generally upheld the Corps’ and EPA’s WOTUS determinations.  For example, a federal appellate court recently upheld the Corps’ determination that a 4.8-acre wetland adjacent to a man-made drainage ditch was a WOTUS.  The ditch was connected to a traditionally navigable water (a river) only through a series of seven miles of other drainage ditches and tributaries.  Nonetheless, the Corps found that the wetland, considered in combination with other similarly situated waters in the region, had a “significant nexus” to the traditionally navigable river.[19]

EPA and the Corps’ New WOTUS Rule

In light of EPA’s and the Corps’ current definitions of WOTUS, as well as how they have applied Justice Kennedy’s “significant nexus” standard since Rapanos, it is difficult to accept assertions that the new WOTUS rule would substantially expand the scope of waters protected by the CWA.  In fact, the new rule is, on its face, narrower than the currently effective rule because the new rule excludes several types of waters—for example, groundwater and swimming pools—that EPA and the Corps have never considered WOTUS but that were not expressly excluded from the definition.

How does the new rule compare to the old rule?

First, the new rule retains the following WOTUS categories without any substantial change:

  • traditionally navigable waters;
  • interstate waters;
  • the territorial sea; and
  • impoundments of waters that are otherwise WOTUS

Second, the new rule deletes the WOTUS category of “other waters” whose use, degradation, or destruction would affect or could affect interstate or foreign commerce.  This is consistent with the views of a majority of the Supreme Court justices, who have stated that WOTUS must have some connection to traditionally navigable waters, regardless of any potential effect on interstate or foreign commerce.

Third, the new rule replaces the “other waters” category with a new “significant nexus” category, and it modifies the “tributaries” and “adjacent wetlands” categories in an effort to ensure that waters within these categories have a “significant nexus” to traditionally navigable waters.

  • Tributaries.  The category of tributaries is not defined in the current rule.  The new rule limits tributaries to tributaries (directly or through another tributary) of traditionally navigable waters, interstate waters, or the territorial sea (rather than of any WOTUS, as under the current rule).  In addition, the new rule defines a tributary as a water that “is characterized by the presence of the physical indicators of bed and banks and an ordinary high water mark.”
  • Adjacent waters.  The current rule includes a category for wetlands adjacent to other WOTUS.  The new rule expands this category to include all waters (not just wetlands) adjacent to traditionally navigable waters, interstate waters, the territorial sea, impoundments, and tributaries.  In addition, the rule defines “adjacent” to mean “bordering, contiguous, or neighboring,” which it further defines to include:
    • Waters separated from a WOTUS to which this category applies only by “constructed dikes or barriers, natural river berms, beach dunes, and the like.”
    • Waters for which any portion is within 100 feet of the ordinary high water mark of a WOTUS to which this category applies.
    • Waters located within the 100-year floodplain, and not more than 1500 feet from the ordinary high water mark, of a WOTUS to which this category applies.
    • Waters for which any portion is within 1500 feet of the high tide line of a traditionally navigable water, interstate water, or the territorial sea, or within 1500 feet of the ordinary high water mark of the Great Lakes.
  • “Significant nexus” waters.  To replace the “other waters” category of the current rule, the new rule includes a new category of waters determined to have a “significant nexus” to a traditionally navigable water, interstate water, or the territorial sea.  The rule includes a more elaborate definition of “significant nexus” than EPA and the Corps’ proposed rule from March 2014.  In addition, the rule limits the waters for which a “significant nexus” may be determined to:
    • Waters that are in one of five categories:  “prairie potholes,” “Carolina bays and Delmarva bays,” “Pocosins,” “Western vernal pools,” and “Texas coastal prairie wetlands”;
    • Waters within the 100-year floodplain of a traditionally navigable water, interstate water, or the territorial sea; or
    • Waters within 4000 feet of the high tide line or ordinary high water mark of a traditionally navigable water, interstate water, the territorial sea, or a WOTUS that is an impoundment or tributary.
Fourth, the new rule retains the current rule’s exclusions from WOTUS for wastewater treatment systems and “prior converted cropland” and adds the following exclusions (which, again, largely reflect existing, informal exclusions):
  • The following ditches:
    • with ephemeral flow that are not a relocated tributary or excavated in a tributary;
    • with intermittent flow that are not a relocated tributary or excavated in a tributary, and that do not drain wetlands; or
    • that do not flow, either directly or indirectly, into a traditionally navigable water, interstate water, or the territorial sea (i.e. that are not a “tributary”).
  • Artificially irrigated areas that would revert to dry land should application of water to the area cease.
  • Artificial lakes and ponds created in dry land, such as farm and stock ponds, irrigation ponds, settling basins, fields flooded for rice growing, log cleaning ponds, and cooling ponds.
  • Artificial reflecting pools, swimming pools, and small ornamental waters created in dry land.
  • Water-filled depressions created in dry land incidental to mining or construction activities.
  • Erosional features, including gullies, rills, and other ephemeral features that do not meet the definition of tributary (for example, because they do not possess a “bed and banks”), as well as non-wetland swales, and “lawfully constructed grassed waterways.”
  • Puddles.
  • Groundwater, included groundwater drained through subsurface drainage systems.
  • “Stormwater control features constructed to convey, treat, or store stormwater that are created in dry land.”
  • Wastewater recycling structures constructed in dry land, detention and retention basins built for wastewater recycling, groundwater recharge basins, percolation ponds built for wastewater recycling, and water distributary structures built for wastewater recycling.

These exclusions apply regardless whether the excluded waters would otherwise be a WOTUS.

In substance, the new rule leaves the definition of WOTUS essentially as it has been since the Supreme Court’s 2006 decision in Rapanos, and not substantially narrower than it was applied before Rapanos.  The “significant nexus” standard has replaced the “could affect interstate commerce” standard, and it has also, in theory, circumscribed the application of the “tributary” and “adjacent waters” category, but the vagueness of the standard has allowed EPA and the Corps to include within the definition of WOTUS almost all waterbodies that would have been included in the definition before Rapanos and the Supreme Court’s 2001 decision in SWANCC.

What the new rule does do, however, is simplify enforcement actions, including citizen suits, for discharging without a permit.  Without the new rule, the agencies (or a citizen suit plaintiff) would need to establish that the waterbody at issue is a traditionally navigable water or that it has a “significant nexus” to a traditionally navigable water.  For most waterbodies, this is not difficult, but for smaller waterbodies and wetlands that are far from the nearest traditionally navigable water, this can require substantial technical information and analysis.[20]  Although ultimately a court is apt to defer to the agency’s determination of a “significant nexus”—but not to the determination of a plaintiff in a citizen suit—the need to establish such a record could dissuade the agency or citizen from bringing the action.  For “tributaries” and “adjacent waters” under the new rule, however, the rule itself categorically determines that these waterbodies have a “significant nexus.”  There will no longer be a need to establish the nexus in each case.  This could have the effect of increasing enforcement actions, even if it does not substantially alter the scope of waterbodies that EPA and the Corps have historically considered to be WOTUS.

Judicial Challenges to the New Rule

Industrial and agricultural organizations will almost certainly challenge the new WOTUS rule.  If Justice Kennedy’s “significant nexus” standard remains the controlling standard, they will argue that the new rule’s WOTUS categories include waterbodies that do not have a “significant nexus” to a traditionally navigable water.  Justice Kennedy’s opinion in Rapanos suggested that EPA and the Corps could protect categories of waterbodies as long as the categories “are likely, in the majority of cases” to include waters with a “significant nexus.”[21] The Court might find that some of the new rule’s categories include too many waterbodies that are unlikely to have a “significant nexus.”  Most vulnerable may be the “tributaries” category, which could include small, ephemeral and intermittent streams (as well as adjacent wetlands and other waters) that are hundreds of miles upstream of the nearest traditionally navigable water.  The rule may also be challenged on the ground that, even if it is consistent with EPA’s and the Corps’ authority under the CWA, the CWA itself exceeds Congress’ authority under the Commerce Clause of the Constitution by regulating activities that arguably have no effect on interstate commerce—such as filling a small, ephemeral stream that is hundreds of miles from the nearest traditionally navigable water.  Any ruling on constitutional grounds, which the Court would try to avoid, could have far-reaching effects not only on the CWA, but on other federal environmental statutes, which are also based on Congress’ Commerce Clause authority.

A challenge to the rule by environmental advocacy organizations is much less likely, although not inconceivable.  A potential argument from this quarter may be that the rule is too narrow because it excludes some waterbodies even if they are determined to have a “significant nexus.”  For example, a large wetland or other waterbody that is not itself a traditionally navigable or interstate water, that is not a tributary to or adjacent to such a water, and that does not fit into any of the subcategories for which a “significant nexus” determination may be made under the new rule, would not be a WOTUS regardless of the extent of its “nexus” to a traditionally navigable water.  But the chances of successfully making such an argument to the current Supreme Court are probably remote.

In the meantime, because the new rule largely reflects EPA’s and the Corps’ current interpretation of WOTUS, it is unlikely to result in any change in the regulatory status quo for most businesses and other entities that are regulated or potentially regulated under the CWA.  The only significant caveat is that it could increase the risk of enforcement actions for discharging without a permit into waterbodies that fall within the new tributary and adjacent waters categories because the rule eliminates the need to establish a “significant nexus” for these waterbodies.  Pending a successful legal challenge to the new rule, or a substantial political shift in Washington, D.C., the rule is likely to continue the broad interpretation of WOTUS that has generally prevailed for the last three decades.

If you have any questions about this rule or the content of this alert, please contact a key contributor.


[1] The rule has not yet been published in the Federal Register, and it is not effective until 60 days after publication. 

[2] Obama Announces New Rule Limiting Water Pollution, The New York Times (May 27, 2015).

[3] Id.

[4] Id.

[5] E.g., H.R. 1732, 114th Congress

[6] See 33 U.S.C. §§ 1311(a), 1342, 1344, 1362(12).  More specifically, the CWA prohibits the “discharge of a pollutant” without a permit from EPA, the Corps, or a state or tribal agency to whom the permit program has been delegated.  The CWA defines “discharge of a pollutant” as “any addition of any pollutant to navigable waters from any point source” (as well as “any addition of any pollutant to the waters of the contiguous zone or the ocean from any point source other than a vessel or other floating craft”).  Id., § 1362(12).  Because the CWA defines (1) “pollutant” to include fill material and almost any type of waste or wastewater, including stormwater, and (2) “point source” as “any discernible, confined and discrete conveyance, including but not limited to any pipe, ditch, . . . container, . . . concentrated animal feeding operation, or vessel,” see 33 U.S.C. § 1362(6), (14), the addition of almost anything to “navigable waters” from a specific source (or to the contiguous zone or ocean from any source other than a vessel) requires a permit unless the CWA provides an exemption.  There are, however, several such exemptions, particularly for agricultural and silvicultural activities.  See, e.g., 33 U.S.C. §§ 1342(l), (p), 1344(f).

[7] 33 U.S.C. § 1362(7).

[8] See 38 Fed. Reg. 13528, 13529 (May 22, 1973).

[9] See 39 Fed. Reg. 12115, 12119 (Apr. 3, 1974); 33 C.F.R. § 209.260 (1973).

[10] Natural Resources Defense Council, Inc. v. Callaway, 392 F. Supp. 685, 686 (D.D.C. 1975).  The legislative history of the CWA includes a statement that Congress intended the term WOTUS to “be given the broadest possible constitutional interpretation.”  S. Conf. Rep. No. 92-1236 at 144 (1972).

[11] Compare 45 Fed. Reg. 33290, 33298, 33424 (May 19, 1980) (EPA’s definition of WOTUS), 51 Fed. Reg. 41206, 41216-17, 41232, 41250-51 (Nov. 13, 1986) (the Corps’ definition of WOTUS), with 40 C.F.R. § 122.2 (2014) (EPA’s definition of WOTUS until the new rule takes effect), 33 C.F.R. § 328.3 (2014) (the Corps’ definition of WOTUS until the new rule takes effect). 

[12] See 33 C.F.R. § 328.3 (2014); 40 C.F.R. § 122.2 (2014).

[13] See, e.g., Gonzales v. Raich, 545 U.S. 1 (2005) (growing marijuana for personal use affects interstate commerce); Wickard v. Filburn, 317 U.S. 111 (1942) (farmer’s growing of wheat for his own consumption affects interstate commerce); but cf. United States v. Lopez, 514 U.S. 549 (1995) (guns in schools do not affect interstate commerce and prohibiting them exceeded Congress’ Commerce Clause power).

[14] Rapanos v. United States, 547 U.S. 715 (2006); Solid Waste Agency of Northern Cook County (SWANCC) v. U.S. Army Corps of Engineers, 531 U.S. 159 (2001).

[15] Rapanos, 547 U.S. at 742, 757.

[16] Id. at 780.

[17] Id. at 810 (Stevens, J., dissenting).

[18] See, e.g., Northern Calif. River Watch v. Healdsburg, 496 F.3d 993, 999-1000 (9th Cir. 2007).

[19] See Precon Development Corp. v. U.S. Army Corps of Engineers, No. 13-2499 (4th Cir., Mar. 10, 2015).

[20] See, e.g., Precon Development Corp. v. U.S. Army Corps of Engineers, No. 13-2499 (4th Cir., Mar. 10, 2015).

[21] Rapanos, 547 U.S. at 781 (Kennedy, J., concurring).

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