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U.S. District Court Applies the Clean Water Act ‘Functional Equivalent’ Standard Set Forth by the U.S. Supreme Court

U.S. District Court Applies the Clean Water Act ‘Functional Equivalent’ Standard Set Forth by the U.S. Supreme Court
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By Ana Schwab and Rebecca Andrews

To determine if the County of Maui required a federal Clean Water Act permit, the U.S. District Court for the District of Hawai’i applied the “functional equivalent” standard set forth by the U.S. Supreme Court in County of Maui v. Hawai’i Wildlife Fund, 140 S.Ct. 1462 (2020). The standard includes criteria for courts to utilize when determining whether or not a discharge into navigable waters requires a National Pollutant Discharge Elimination System (NPDES) permit, as prescribed in the Clean Water Act. [Hawai’i Wildlife Fund v. County of Maui, ___F.Supp.3d___, Case No. 12-00198 (D. HI July 26, 2021).]

Factual and Procedural Background

The County of Maui operates a wastewater reclamation facility on the island of Maui, Hawai’i. The facility collects sewage, treats it, and disposes of the treated water underground in four wells. This effluent then travels a further half mile or so, through groundwater, to the Pacific Ocean, although with certain components, like nitrogen, being reduced before the wastewater reaches the ocean.

Monitors at a handful of locations near the shoreline detected less than 2 percent of the wastewater from two of the four wells. No scientific study conclusively established the path of the other 98 percent of the wastewater. The 2-percent of treated wastewater reaching the ocean amounts to tens of thousands of gallons every day. While the parties and court could not point to the exact path of the rest of the 98 percent of wastewater, it is likely that that remainder enters the Pacific Ocean within a few miles of the facility.

With a few exceptions, the Clean Water Act (CWA) requires a permit when there is the discharge of any pollutant to a navigable water. The Ninth Circuit previously heard this case and ruled that the County of Maui’s discharges required an NPDES permit as the pollution and pollutants were “fairly traceable” to their injection wells. On certiorari, the U.S. Supreme Court ruled that the fairly traceable standard was too broad and replaced the standard with the functional equivalent standard. With the new standard, the Court provided a non-exclusive framework for other courts to utilize when reviewing this question:

(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 sources, (6) the manner by or the area in which the pollutant enters the navigable waters, [and] (7) the degree to which the pollution (at that point) has maintained its specific identify. Time and distance will be the most important factors in most cases, but not necessarily every case.

The District Court’s Decision

On remand, the U.S. District Court applied the functional equivalent standard articulated by the Supreme Court to determine whether the discharges from the County of Maui’s injection wells were the functional equivalent to a discharge from a point source. The court applied seven factors identified by the Supreme Court, one factor from U.S. Environmental Protection Agency (EPA) Guidance, and added its own factor as follows:


  • Time—The court found that the time between the effluent leaving the injection wells and reaching the ocean was less than “many years.” The court concluded the amount of time was within the window that the Supreme Court expected to require a permit, reasoning that “even if the court double[d] the longest time measured at the seeps” it would still be less time than the ceiling of this factor set forth.


  • Distance—The court found that the distance from the injection wells to the ocean, when calculated both horizontally and vertically, was a “relatively short distance.” Further the court found that even when the pollutant arrived diluted, its journey to the ocean was short enough and less than the “50-mile extreme” set forth by the Supreme Court.


  • Nature of the Material the Pollutant Travels—The court quickly found that this factor weighed in favor of no permit being required. The court found that the effluent travels and mixes with “other waters flowing through rock and other substances.”


  • Extent to Which the Pollutant is Diluted or Chemically Changed as it Travels—Similar to factor three, the court here found that while there is a pollutant entering the navigable waters, the pollutant is significantly diluted or otherwise removed. Despite the presence of pollutants, this factor weighed in favor of no permit being required as it was significantly diluted or otherwise removed.


  • Amount of the Pollutant Entering the Navigable Waters Relative to the Amount of the Pollutant that Leaves the Point Source—The court found that this factor weighed in favor of requiring a permit. It reasoned that whether or not some of the pollutant is removed, pollutants still reach the ocean.


  • Manner By or Area in Which the Pollutant Enters the Navigable Waters—The court reasoned that the manner by which the pollutant enters the ocean is partially known but not completely known. The court reasoned that the lack of complete information in this factor did not weigh in favor or against a permit.


  • Degree to Which the Pollution Maintains its Specific Identity—The court weighted this factor in favor of needing a permit. Its reasoning being that, even if some of the pollutants are diluted or otherwise removed, the “wastewater maintains its specific identity as polluted water emanating from the wells.”


  • System Design and Performance—Following the Supreme Court decision, the EPA issued guidance on the application of the functional equivalent test. In its guidance, the EPA urged courts to review the design and performance of facilities as it pertains to the factors put forth by the Supreme Court. Ultimately, the District Court found that this factor did not weigh in favor or against the permit in this matter. The reason being is that the Supreme Court and all parties concur on the purpose of the treatment plants and from there to flow to the ocean.


  • Volume of Wastewater Reaching Navigable Waters—The court added this factor to those provided by the Supreme Court and the EPA. The court stated that it was necessary to separately consider the volume of wastewater reaching the ocean as the other factors had not considered the “immensity of the wastewater volume.” The court reasoned that the “raw volume [f wastewater] is so high that it is difficult to imagine why it should be allowed to continue without an NPDES permit.”

The court ultimately found that even if the ninth factor were not considered, the balancing of all the other factors weighted heavily towards the County being required to have a NPDES permit.

Conclusion and Implications

This case is the first published case in which a court has applied the “functional equivalent” standard created by the U.S. Supreme Court. The fact-specific nature of the standard means this case will likely be the first of many to come. The District Court’s opinion is available online at: