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U.S. Supreme Court Establishes New Test Further Defining the Scope of Water Discharges Which Require a Permit Under the Clean Water Act

Client Alert


The United States Supreme Court recently issued a 6-3 decision in County of Maui v. Hawaii Wildlife Fund holding that the Clean Water Act (“CWA” or “Act”) requires a permit for a point source that emits pollutants into navigable waters through groundwater if the emission is the “functional equivalent” of a direct discharge from the point source into navigable waters. The decision establishes a new test further defining the scope of water discharges which require a  permit under the CWA.  The Court declined to elaborate a precise test for “functional equivalent,” but left the standard for elaboration “through decisions in individual cases.”  Accordingly, agencies will need to be mindful that in many cases they will need a National Pollutant Discharge Elimination System (NPDES) permit for the discharge of effluent through groundwater and for groundwater recharge projects.  Failure to obtain a NPDES permit when required can result in fines, injunctive relief and exposure to attorney fee awards. 


The CWA prohibits the addition of a pollutant from “any point source” to navigable waters of the United States without a permit through the National Pollutant Discharge Elimination System. The Act defines “pollutant” broadly, and defines a “point source” as any discernible, confined and discrete conveyance from which pollutants are or may be discharged, including any container, pipe, ditch, channel, tunnel, conduit, or well.  It defines the term “discharge of a pollutant” as any addition of any pollutant to navigable waters, including navigable streams, rivers, the ocean, or coastal waters, from any point source. The Act then uses those terms in making unlawful the discharge of any pollutant by any person without an appropriate permit.

The County of Maui’s Lahaina Wastewater Reclamation Facility treats wastewater by injecting treated wastewater (“effluent”) into underground injection control wells, which is a common method used by municipalities to dispose of effluent. Before injection, effluent is treated to meet Hawaii’s highest standards for recycled water, some of which is used for resort and golf course irrigation. Upon injection, effluent mixes with groundwater and disperses vertically and horizontally, eventually migrating to the ocean approximately a half-mile away. Over 90% of the effluent/groundwater mixture enters the ocean through diffuse flow, with no identifiable entry point. Reports indicated that the U.S. Environmental Protection Agency and the Hawaii Department of Health understood that the wastewater entered the ocean, and neither agency suggested that this result required NPDES permitting.

In 2012, several environmental groups brought a citizens’ CWA lawsuit against the County of Maui (“County”) in Hawaii. The environmental groups claimed the County was discharging a pollutant into navigable waters, specifically the Pacific Ocean, without a permit required by the CWA.

The District Court found a considerable amount of effluent from the wells ended up in the Pacific Ocean and found the discharge as functionally discharged from a point source into a navigable water due to the clearly ascertainable path the water had to the ocean. The Ninth Circuit affirmed the District Court, but added that a permit is required when the pollutants are “fairly traceable” from the point source to a navigable water, such that the discharge is the functional equivalent of a discharge into the navigable water. The County petitioned for certiorari and the Supreme Court granted the petition.

Supreme Court Decision

The issue that came before the United States Supreme Court was whether the CWA requires a permit when pollutants originate from a point source but are conveyed to navigable waters by a nonpoint source, such as groundwater. The Supreme Court held the CWA requires a permit for pollutants that make their way into navigable waters through groundwater if the emission is the “functional equivalent” of a direct discharge from the point source into navigable waters.

The Court explained the statute’s words reflect Congress’ basic aim to provide federal regulation of identifiable sources of pollutants entering navigable waters without undermining the States’ longstanding regulatory authority over land and groundwater.  Further, the Court reasoned whether pollutants that arrive at navigable waters after traveling through groundwater are “from” a point source depends upon how similar (or different) the particular discharge is as compared to a direct discharge.  The court found that the phrase “functional equivalent” best captures circumstances in which Congress intended to require a federal permit.

The new standard adopted by the Supreme Court is fact-specific and primarily takes into consideration time and distance.  For example, water that travels a few feet through groundwater to reach navigable water is clearly the “functional equivalent” of a direct discharge from a point source.  However, water that must travel fifty miles to reach navigable waters, and blends with other waters before reaching navigable waters after fifty years would not be the “functional equivalent” of a direct discharge. 

The Court identified other factors that may prove relevant (depending on the circumstances of a particular case) such as: (1) transit time, (2) distance traveled, (3) the nature of the material through which the pollutant travels, (4) the extent to which the pollutant is diluted or chemically changed as it travels, (5) the amount of pollutant entering the navigable waters relative to the amount of the pollutant that leaves the point source, (6) the manner by (or area in) which the pollutant enters the navigable waters, and (7) the degree to which the pollution has maintained its specific identity. Although time and distance will be the most important factors in most cases, this may not be true in every case.  The Court essentially acknowledged there will be some cases that are tough calls, and noted that the Environmental Protection Agency may issue administrative guidance.

The Supreme Court’s opinion was authored by Justice Breyer and was joined by Chief Justice Roberts and Justices Ginsburg, Sotomayor, Kagen and Kavanaugh, with Justice Kavanaugh filing a concurring opinion. Justice Thomas, joined by Justice Gorsuch, wrote a dissent arguing the CWA should be interpreted to apply when a point source discharges pollutants directly into navigable waters, and Justice Alito issued a separate dissent arguing that the Court’s majority opinion does not provide clear guidance.  The decision vacated the ruling of the United States Court of Appeals for the Ninth Circuit, and remanded the case with instructions to the lower courts to apply the new standard. The Ninth Circuit’s decision on remand may shed additional light on how this rule will be applied. 

Impact of This Decision

Agencies will need to review the factors in the Court’s new test and anticipate the likely instances where they would be expected to obtain a NPDES permit for the discharge of effluent through groundwater and for groundwater recharge projects.  There is also a likelihood of an increase in CWA litigation related to such projects. Failure to obtain an NPDES permit when required can result in fines, injunctive relief and exposure to attorney fee awards.  The Supreme Court acknowledged this fact but noted that when there is a violation, courts have broad discretion to set a penalty that takes into account many factors, including “good-faith efforts to comply” with the Act, the “seriousness of the violation,” the “economic impact of the penalty on the violator,” and “such other matters as justice may require.” See 33 U.S.C. §1319(d). Finally, the Court stated, “We expect that district judges will exercise their discretion mindful, as we are, of the complexities inherent to the context of indirect discharges through groundwater, so as to calibrate the Act’s penalties. . . .”

For further information, please contact Christine Carson, Alondra Espinosa or Andrea Oguntula from Aleshire & Wynder, LLP’s Water Practice Group at (949) 223-1170. Disclaimer:  Aleshire & Wynder, LLP legal alerts are not intended as legal advice.  Additional facts or future developments may affect subjects contained herein.  Please seek legal advice before acting or relying upon any information in this communication.