Clean Water Act Permits Now Required When a Point Source Discharge Through Groundwater is the “Functional Equivalent” of a Direct Discharge to Navigable Waters

Water Quality Law  

April 24, 2020

For those seeking certainty and bright line tests, the U.S. Supreme Court is apparently not the right venue. On April 23, 2020, the Supreme Court issued a 6-3 majority opinion in County of Maui, Hawaii v. Hawaii Wildlife Fund, et al., 590 U.S. ___ (2020) narrowing the Ninth Circuit and producing a new murky rule for when federal Clean Water Act permits are required for point sources discharges to groundwater that ultimately reach navigable water.  The Supreme Court held that a National Pollutant Discharge Elimination System (NPDES) permit is required “if the addition of the pollutants through groundwater is the functional equivalent of a direct discharge from the point source into navigable waters.”  Slip Op. at 1 (emphasis added).  However, the Court failed to provide much clarity on what constitutes a “functional equivalent,” just a short list of potential considerations.

The case centered around the County of Maui’s (“Maui”) Lahaina Wastewater Reclamation Facility (“Facility”), which treats domestic wastewater and discharges the treated effluent into groundwater wells that eventually flow to the Pacific Ocean.  The plaintiffs argued that Maui needed an NPDES permit because pollutants from the effluent were detected in the ocean, a traditional navigable water subject to regulation under the Clean Water Act, offshore of this Hawaiian island.  Maui did not have an NPDES permit for the Facility, because the Facility discharged first to groundwater, which is not a federal jurisdictional water to which the Clean Water Act’s permitting requirement applies.

The question before the Supreme Court was whether “pollution that reaches navigable waters only through groundwater [is] pollution that is ‘from’ a point source” requiring an NPDES permit.  Id. at 4.  The majority articulated a standard that an NPDES permit is required “when there is a direct discharge from a point source into a navigable water or when there is the functional equivalent of a direct discharge” from a point source.  Id. at 15.  This standard is different, and somewhat narrower, than the Ninth Circuit’s previous “fairly traceable” test.  Recognizing that the term “functional equivalent” is not easy to apply on its face, the Supreme Court further stated that a discharge requires a permit “when a point source directly deposits pollutants into navigable waters, or when the discharge reaches the same result through roughly similar means.”  Id.  To assist with determining what might be “roughly similar,” the majority opinion also provided several factors that might be used, including the pollutant’s travel time between the discharge point and the navigable water; the distance traveled; the material through which the discharge travels; dilution or chemical changes during travel; and other factors, although the list is admittedly not exhaustive.

Justice Alito’s dissent from the majority opinion articulates several concerns about the vagueness of the majority’s “functional equivalent” rule.  Alito’s dissent raises concerns about the ability for regulators and lower courts to consistently apply the rule, given that the majority only provides extreme examples of when a hypothetical discharge would be a functional equivalent (when the discharge point is mere feet from the navigable water) and when it would not (when the pollutant travels hundreds of miles over a 100 year period before reaching the navigable water).  Justice Alito cautions that this rule, rather than one that would limit the Clean Water Act’s permit requirement to only those direct discharges from point sources to navigable waters, does not provide sufficient guidance to dischargers, regulators, and courts in determining whether a discharge requires an NPDES permit.  In addition, the non-exhaustive list of potential factors that influence whether a discharge is a functional equivalent further muddy the rule.

The functional equivalent standard will inevitably trigger confusion, additional disputes, and more litigation as dischargers, interest groups, and regulators attempt to respond to the new rule in situations that fall between the extreme ends of the spectrum.