There were two important developments for the Clean Water Act (“CWA”) in April 2020. First, on April 21, 2020, the Environmental Protection Agency (“EPA”) published the Navigable Waters Protection Rule (NWR”) in order to define the regulatory scope of the “waters of the United States.”[1] The new definition now includes the following four categories of jurisdictional waters, including: 1) the territorial seas and traditional navigable waters; 2) perennial and intermittent tributaries that contribute surface water flow to such waters; 3) certain lakes, ponds, and impoundments of jurisdictional waters; and 4) wetlands adjacent to other jurisdictional waters. The new rule specifically excludes from the definition of “navigable waters” groundwater; ephemeral features; diffuse stormwater runoff; ditches that are not traditional navigable waters, tributaries, or that are not constructed in adjacent wetlands; artificially irrigated areas; artificial lakes and ponds that do not qualify as impoundments of jurisdictional waters; stormwater control features constructed in uplands; and waste treatment systems.

The NWR is a replacement rule for the Obama Administration’s Clean Water Rule (“CWR”), which was repealed by the Trump Administration in September 2019. The CWR and associated case law[2] established the “sufficient nexus principle” which allowed jurisdiction over wetlands with a shallow subsurface connection to a navigable water. The NWR eliminates the “significant nexus test,” and now does not allow jurisdiction over wetlands connected to navigable waters by subsurface flow as these wetlands are not “adjacent” to navigable waters under the new rule. This rule will take effect on June 22, 2020.

Two days later, on April 23, 2020, the Supreme Court of the United States published its opinion in the County of Maui v. Hawaii Wildlife Fund[3] case. The Supreme Court considered whether the CWA requires permits for point source discharges of pollutants that travel through nonpoint sources, specifically groundwater, to reach navigable waters. The Supreme Court held that only point source discharges to groundwater that are the “functional equivalent” of direct discharges into navigable waters require CWA permits.

Pursuant to the CWA, pollutants cannot be discharged from a point source to navigable waters without a permit from either the U.S. Environmental Protection Agency or an authorized state agency.[4]    For years, the County of Maui (“Maui”) has been discharging partially treated wastewater from its sewage reclamation facility into nearby groundwater. The discharge then travels in the groundwater for about half a mile before reaching the Pacific Ocean.  A citizens group, Hawaii Wildlife Fund, brought a CWA suit against Maui alleging it was discharging a pollutant into navigable waters without a permit.

The Supreme Court rejected the Ninth Circuit Court of Appeal’s holding that a permit is required for non-direct discharges that “are fairly traceable from the point source to a navigable water.” The Court reasoned that, “virtually all water, polluted or not, eventually makes its way to navigable water,” and that the legislative intent behind the CWA did not intend the EPA to have “permitting authority over the release of pollutants that reach navigable waters many years after their release and in highly diluted forms.” Additionally, the Court noted that the Ninth Circuit’s use of the word “from” left the method of transportation to a navigable water open to “bizarre” interpretations. The Supreme Court also pointed out that the CWA does not explicitly regulate nonpoint sources or groundwater.

The U.S. Supreme Court held, however, that CWA’s permitting program was also not designed to exclude all releases of pollutants that travel through groundwater. The Supreme Court explained that this would create a loophole allowing a company discharging through a pipe to “simply move the pipe back, perhaps only a few hundred yards, so that the pollution must travel though at least some groundwater before reaching the sea.”    Instead, the Supreme Court concluded that CWA requires a permit when “there is the functional equivalent of direct discharge.” The Supreme Court did not outline a test for “functional equivalent,” but rather left it up to the courts to decide on a case-by-case basis.  To aid other courts in reaching a determination, the Supreme Court gave a list of suggested factors for consideration including:

  • “transit time,
  • distance traveled,
  • the nature of the material through which the pollutant travels,
  • the extent to which the pollutant is diluted or chemically changed as it travels,
  • the amount of pollutant entering the navigable waters relative to the amount of the pollutant that leaves the point source,
  • the matter by or area in which the pollutant enters the navigable waters, and
  • the degree to which the pollution (at that point) has maintained its specific identify.”

The Supreme Court noted that, “time and distance [between the point source and the navigable waters] will be the most important factors in most cases, but not necessarily every case.”

While the Supreme Court failed to establish a bright line rule, the opinion offers a middle ground between industry groups that want all releases of pollutants to groundwater excluded from the permitting program under the CWA, and environmental groups that argue a permit is required when a pollutant can be traced back to a point source.

The opinion of the Court was authored by Justice Breyer and was joined by Chief Justice Roberts and Justices Ginsburg, Sotomayor, Kagan, and Kavanaugh. Justice Kavanaugh filed a concurring opinion. Justice Alito filed a dissent, and Justice Thomas filed a separate dissent which was joined by Justice Gorsuch.

[1] Full text of the final rule is available at

[2] Rapanos v. United States, 547 US 715 (2006).

[3] County of Maui v. Hawaii Wildlife Fund, 590 US __ (2020).

[4] Federal Water Pollution Control Act, §§ 301(a), 502(12)(A), as amended by the Federal Water Pollution Control Act Amendments of 1972 (Clean Water Act) § 2, 86 Stat. 844, 886, 33 U.S.C. §§ 1311(a), 1262(12)(A).