Middle Ground, or Muddy Waters? SCOTUS Issues Vague Rule in Clean Water Act Decision

Last week, the U.S. Supreme Court issued a long-awaited decision in County of Maui v. Hawaii Wildlife Fund et al., 590 U.S. __ (2020), in which it determined that the Clean Water Act (CWA) requirements for a National Pollutant Discharge Elimination System (NPDES) permit for point source discharges of pollutants do apply in certain circumstances to effluent that reaches waters of the United States via groundwater. But under what circumstances? Plaintiff environmental groups argued for the Ninth Circuit’s decision that CWA permitting requirements apply when effluent in a navigable water is “fairly traceable” through groundwater to a point source. The County of Maui, however, argued for a bright-line test, pursuant to which no NPDES permit would be required unless a point source directly discharges into navigable water (also known under the CWA as a “water of the United States”). In a 6-3 decision, the Supreme Court rejected both tests proposed by the parties and aimed for the middle, holding that the CWA requires a NPDES permit when a direct discharge to groundwater “is the functional equivalent of a direct discharge from the point source into navigable waters.”

The case is centered around the County of Maui’s wastewater facility that receives and partially treats wastewater before pumping it into the ground. Effluent from that treated water traveled approximately half a mile through the groundwater before reaching the Pacific Ocean. When pollutants from the effluent were detected in the ocean (a navigable water under the CWA), environmental groups brought a CWA citizens’ suit alleging that the County needed a NPDES permit, even though the CWA’s permitting requirements generally do not apply to direct discharges to groundwater.

In rejecting the Ninth Circuit’s “fairly traceable” test, the Court explained its concern that the rule was too broad, potentially requiring a permit for the release of pollutants to groundwater that could take hundreds of years, and much farther distances, to reach navigable waters. Additionally, the Court recognized that the CWA leaves significant authority to the States to regulate groundwater pollution, and that Congress did not intend to “seriously interfere with this state responsibility.”

While the Supreme Court’s “functional equivalent” test is narrower than the “fairly traceable” test, it lacks the clarity of the “direct discharge” test. In addition, the “functional equivalent” test is a brand new test, that does not claim to be based in, or related to, Justice Kennedy’s “significant nexus” test established and explained in the 2006 Rapanos v. United States decision. On the one hand, the Supreme Court said that a NPDES permit is clearly required where a pipe emits pollutants that travel a few feet through groundwater to navigable waters. On the other hand, if the pollutants enter groundwater at a point 50 miles from a navigable water and travel though groundwater for “many years,” the Court explained that a permit “likely” is not required. For cases between those extremes, the outcome of the Maui case is murky. Anticipating such challenges, the Supreme Court added that a permit would be required where “a point source directly deposits pollutants into navigable waters, or when the discharge reaches the same result through roughly similar means.” To determine “roughly similar means,” it offered a non-exhaustive list of relevant factors, stating that time and distance are the most important: “(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.” Despite these guidelines, the Court’s decision leaves significant room for uncertainty.

Going forward, it is clear that CWA permitting for point source discharges that migrate through groundwater to waters of the United States will depend on the specific facts and circumstances involved, and that uncertainty in the regulatory field will continue for the foreseeable future. This uncertainty could be particularly problematic for determining permitting requirements for a variety of encouraged practices, such as the use of capture and infiltration and natural bio-filtration best management practices to treat stormwater and other types of pollution. In addition, while Water Boards in California already require state law permits (Waste Discharge Requirements or WDRs) for discharges to groundwater or that threaten to migrate to groundwater, the conditions of those WDRs are currently based on consideration of groundwater, not surface water quality standards. In the event that a NPDES permit is now also required under Maui for discharges to groundwater that make their way to surface waters of the United States, there is an open question as to whether Water Boards will amend the conditions of those discharge permits in a material way.  In any event, there inevitably will be further litigation as dischargers, regulators, and interest groups test the nuances of the Court’s “functional equivalent” rule.

Another notable facet of the Maui case has less to do with the specific details of the decision, and more with how the Justices might decide future questions under the CWA. Justice Kavanaugh’s concurring opinion is particularly noteworthy:  He wrote that he agreed with the Maui majority “in full,” but in explaining the reasons for his concurrence, he relied heavily on Justice Scalia’s concurring opinion in the  Rapanos decision. Rapanos addressed whether particular types of watercourses are within the CWA’s jurisdiction (i.e. what should be considered a “navigable water,” defined as “waters of the United States”). Justice Scalia opined “waters of the United States” should be defined quite narrowly, requiring relatively permanent flow and some connection to waters that are navigable “in fact.” 

Coincidentally, last week the Trump Administration also published its revised definition of “navigable waters” (also known as the “Waters of the United States,” or “WOTUS” Rule). The revised WOTUS Rule closely adheres to Justice Scalia’s interpretation in Rapanos. Because Rapanos was a plurality decision in which Justice Scalia’s opinion was joined by three others, Justice Kavanaugh’s reliance on it signals the import that the opinion may continue to have on the Supreme Court’s review of future CWA cases, particularly Supreme Court Review of the new WOTUS Rule. (For our additional analysis of the WOTUS Rule, click here.) It would certainly appear from his concurrence that Justice Kavanaugh is likely to look favorably on the Trump Administration’s new WOTUS rule.