The scope of the Clean Water Act (“CWA”) expanded under the Supreme Court’s ruling in County of Maui v. Hawaii Wildlife Fund, 590 U.S. ___ (2020). The Court found that the CWA requirement for a permit prior to discharging a pollutant to navigable water could apply to pollutant discharges to groundwater that subsequently travel to navigable waters.

The CWA forbids the addition of any pollutant from a point source to navigable waters without the requisite permit.   The County of Maui operates a wastewater treatment facility (“Facility”).  The Facility collects sewage, treats it, and then pumps the effluent into groundwater hundreds of feet underground.  The effluent then travels approximately one half mile through groundwater to the ocean.  The Facility did not believe it needed a permit for these activities because the effluent was discharged directly to groundwater, not a navigable water.  In 2012, several environmental groups sued the Facility under the CWA, arguing that the effluent discharge required a permit because it was a pollutant discharged to navigable waters through the groundwater.

The Court grappled with the proper meaning and scope of the word “from” in the context of the CWA’s prohibition on the addition of pollutants to navigable water from a point source.  Wary of granting the EPA unlimited reach, the Court did not want to interpret “from” in a way that would have applied the CWA to all pollutant discharges because “[v]irtually all water, polluted or not, eventually makes its way to navigable water.”  The Court did not believe that Congress intended to grant the EPA such broad authority, which could enable the EPA to require permits for “bizarre” circumstances, such as “pollutants carried to navigable waters on a bird’s feathers, or…the 100-year migration of pollutants through 250 miles of groundwater to a river.”  Furthermore, the Court opined that the regulation of groundwater and non-point source pollution lies outside of EPA’s mandate under the CWA.  Rather, the Court determined Congress left regulation of groundwater and non-point source pollution to the states because the CWA does not specifically provide the EPA with authority to regulate those types of pollution discharges.

Conversely, the Court acknowledged that a narrow interpretation of the word “from” to preclude the applicability of the CWA if there were any intermediary between the discharge and navigable water would completely undermine the goals of the CWA.  As an example, the Court hypothesized that a facility owner could avoid the CWA by moving a discharge pipe back a few yards from a navigable water. Thus, the Court rejected the interpretation that the CWA’s permit requirement does not apply if a pollutant has to travel through any amount of groundwater before reaching navigable waters.

Instead, the Court adopted a middle ground interpretation of the CWA by holding that the CWA prohibits a direct discharge of a pollutant from a point source into navigable waters or “the functional equivalent of a direct discharge.”  That interpretation applies to pollutant discharges to navigable waters “through roughly similar means” as a direct discharge to navigable water.  In other words, context will determine whether the permitting requirements apply for pollutant discharges that may not be directly to navigable water but nonetheless make their way to navigable water.

Acknowledging the difficulty of administering the “functional equivalent” test, the Court outlined important factors to consider when determining the applicability of the permit requirement, including pollutant transfer time and distance traveled.  Other factors could include: the nature of the material the pollutant travels through; the extent to which the pollutant dilutes or changes as it travels; the amount of pollutant entering navigable waters compared to the point source amount; the manner in which the pollutant is discharged to navigable waters; and the degree to which the pollutant has maintained its identity.

The Court encouraged states to mitigate any harms that the Court’s decision may have.  For example, the Court suggested general permits for recurring situations, or issuing permits based on best practices.

This case makes clear that the EPA could regulate pollutant discharges that, although not directly discharged to a navigable water, reach a navigable waterway.  The Maui decision could greatly expand the reach of the EPA and lead to the imposition of further permitting requirements for more types of pollutant discharges.  A complicating issue is the lack of guidance from the Court.  Although the Court provided factors regarding when a discharge requires a permit, in many cases there will be uncertainty as to whether the CWA permitting standards and requirements apply. It will be up to future courts to refine this doctrine and for states and the EPA to interpret when a discharge is “functionally equivalent” to a direct discharge.

It is worth noting that the Court’s decision in Maui is in line with the Seventh Circuit decision in Vill. of Oconomowoc Lake v. Dayton Hudson Corp., 24 F.3d 962 (7th Cir. 1994).  In that case, citizens brought a CWA suit against the owner of a distribution center claiming that the stormwater pond used for surface water management on the site discharged pollutants into groundwater.  The Seventh Circuit found no federal CWA violation because there was no hydrological connection between the groundwater and a navigable water.  This case can be interpreted to align with Maui. The plaintiff in Dayton Hudson had essentially asserted that a discharge to groundwater was per se a discharge to navigable water.  The Seventh Circuit rejected that broad interpretation, as did the Court in Maui.   Instead, the Seventh Circuit found there was no hydrological connection between the stormwater pond and navigable water, thus finding no CWA violation.

In Wisconsin’s application of its delegated authority under the CWA, unlike under federal law, permits are required for certain point source discharges to groundwater. Wisconsin’s permitting requirement applies to navigable waters and “drainage systems and other surface water or groundwater, natural or artificial, public or private within the state or under its jurisdiction…” Wis. Stat. § 283.01(20) (emphasis added).  Based on that broad definition, Wisconsin regulates land application discharges like biosolids and manure spreading via Wisconsin Pollutant Discharge Elimination System (WPDES) permits.  Because Wisconsin already regulates discharges of pollutants to groundwater, The Court’s decision in Maui is unlikely to have a significant impact on Wisconsin’s discharge permitting requirements.

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