The United States Supreme Court in County of Maui v. Hawaii Wildlife Fund, 590 U.S. ___ (2020) issued a landmark decision involving the Clean Water Act (CWA), holding that a permit is required when there is a direct discharge of a pollutant from a point source or when there is a “functional equivalent” into navigable waters. The County of Maui owns and operates four wells at the Lahaina Facility, the principal municipal wastewater treatment plant for West Maui. This plant receives approximately 4 million gallons of sewage every day. The Lahaina Facility treats the sewage and pumps the treated water into the ground through its wells. Some of the effluent travels through groundwater and reaches the Pacific Ocean. In County of Maui, the Supreme Court grabbled with the issue of 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 purpose of the CWA is to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters. Section 301 of the Act (33 U.S.C. § 1311) prohibits the discharge of any pollutant into navigable waters by any person from a point source, unless the discharger obtains a National Pollutant Discharge Elimination System (NPDES) permit from the Environmental Protection Agency (EPA).
Maui challenged the necessity of the NPDES permit, arguing that a permit is only required if a point source ultimately delivers the pollutant to navigable waters. Thus, if a pollutant travels through groundwater, then the groundwater, a non-point source, is the conveyance and no permit should be required. The Solicitor General, in support of Maui’s position, argued that the proper interpretation of the statute should exclude the release of pollutants to groundwater, even when such release could result in the conveyance to navigable waters via groundwater. Conversely, environmental groups argued for a broad interpretation of the statute, which covered all pollutants that are “fairly traceable” to a point source.
The Supreme Court rejected both interpretations, opting for a middle ground approach. It created a multi-factor test to determine whether a pollution discharge is the “functional equivalent” of a direct discharge to surface waters. The Court provided that the functional equivalent test must be applied on a case-by-case basis, evaluating a non-exhaustive list of seven factors, including:
- (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 (at that point) has maintained its specific identity. The Court noted that the time and distance factors will often be the most important considerations. Applying the test to the LWRF, the Court found that the discharge of pollutants into navigable waters via groundwater required a permit under the CWA.
In reaching its compromise position, the Court reasoned that the narrow interpretation urged by the Solicitor General would seriously interfere with the EPA’s ability to regulate point source discharges and that Congress would not have intended to create such a large and obvious loophole. Similarly, in declining to apply Chevron deference to the Agency’s interpretation, the Court reasoned that EPA’s interpretation was unreasonable because it would create an easy loophole to circumvent the CWA’s basic purposes. Interestingly, the Court acknowledged the limitations of its “functional equivalent” test, stating that it “does not, on its own, clearly explain how to deal with middle instances. But there are too many potentially relevant factors applicable to factually different cases for this Court now to use more specific language.” However, the Court expressed optimism that additional guidance will be provided in the future through court decisions and administrative guidance from the EPA.