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EPA Narrowly Defines Discharges into Groundwater that Are Subject to Clean Water Act Permitting

December 14, 2020

Draft guidance from the US Environmental Protection Agency provides a clearer look at how the agency intends to apply the US Supreme Court's "functional equivalent" analysis to determine when National Pollutant Discharge Elimination System permits are required for discharges of pollutants reaching waters of the United States through groundwater.

The US Environmental Protection Agency (EPA) published draft guidance in the Federal Register on December 4 clarifying how to apply the US Supreme Court's County of Maui v. Hawaii Wildlife Fund decision to the National Pollutant Discharge Elimination System (NPDES) permit program. The draft guidance explains that the Maui decision did not alter the existing structure of the NPDES permit program; it only provided additional analysis to be considered in a subset of cases involving discharges of pollutants to groundwater that reach waters of the United States. In those cases, EPA states that permitting agencies should evaluate eight factors to determine if discharges of pollutants that reach waters of the United States via groundwater are the "functional equivalent" of direct discharges to waters of the United States, and thus require permits. EPA concludes that the impact of the Maui decision on the NPDES permit program should be limited as the number of NPDES permits issued for such discharges should remain a small percentage of the overall number of permits issued.

Background

The Clean Water Act (CWA) prohibits the "discharge of a pollutant" from a "point source" to "navigable waters" unless it is authorized, usually through NPDES permits. The CWA defines "Navigable waters" as "the waters of the United States, including the territorial seas[.]"

Until the Maui decision, circuits were split on whether NPDES permits were required when a pollutant was discharged from a point source into groundwater that then reached navigable waters. As discussed in a previous Law Flash, the Supreme Court held in Maui that a NPDES permit is required for a discharge of pollutants traveling through groundwater if the discharge is the "functional equivalent of a direct discharge from the point source into navigable waters."

Draft EPA Guidance

The draft guidance offers EPA's interpretation of the Court's "functional equivalent" analysis within the context of the NPDES permitting program, arguably adopting a narrow view of which discharges to groundwater will require a NPDES permit.

The guidance emphasizes the Maui decision does not alter the threshold conditions required to trigger the NPDES permit requirement: (1) there must be an actual discharge of a pollutant to a water of the United States, and (2) the discharge of a pollutant must be from a "point source." If these threshold conditions are satisfied and the pollutant reaches waters of the United States via groundwater, then the Court's "functional equivalent" analysis should be considered to determine if a permit is required.

EPA explains that the "functional equivalent" analysis calls for consideration of many potentially relevant factors, including the non-exhaustive list of seven factors provided in Maui. EPA also offers an eighth factor it believes is relevant to the analysis: the design and performance of the system or facility. According to EPA, information regarding how the facility has engineered, or plans to engineer, the transfer, storage, treatment, or discharge of wastewater can inform the scope and extent of the "functional equivalent" analysis.

Thus, the potentially relevant factors to consider in the "functional equivalent" analysis under EPA’s guidance include:

  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;
  7. The degree to which the pollution (at that point) has maintained its specific identity; and
  8. The design and performance of the system or facility from which the pollutant is released.

EPA further explains its view that what happens to a pollutant when it travels through the groundwater and reaches waters of the United States is critical to the "functional equivalent" analysis. If the composition or concentration of the pollutant when it reaches a water of the United States is different from the pollutant's composition or concentration as initially discharged, either from chemical or biological interaction with soils, microbes, plants, groundwater, other pollutants, or from physical attenuation or dilution, the discharge via groundwater might not be functionally equivalent to a direct discharge to navigable waters under EPA’s guidance.

EPA clarifies that the Maui decision does not require permitting authorities to assume discharges to groundwater that occur near a water of the United States are functionally equivalent to direct discharges. EPA also notes that a mere allegation that a point source discharge is or may be reaching waters of the United States via groundwater will not trigger a permit requirement. Finally, the guidance emphasizes that a demonstration that pollutants released from a point source have reached or will reach a water of the United States via groundwater does not necessarily result in a permit requirement; rather, it only triggers the "functional equivalent" analysis.

The guidance characterizes the Maui decision as likely to have a limited impact on the number of required permits, noting that EPA expects the issuance of NPDES permits for point source discharges reaching waters of the United States via groundwater to remain a small percentage of the overall number of permits issued. However, EPA also advises obtaining a permit before initiating the discharge of pollutants into waters of the United States to avoid violating the CWA.

Implications

EPA’s draft guidance represents a narrow reading of Maui that would limit the circumstances under which a NPDES permit is required for discharges into groundwater. Through the guidance, EPA places a gloss on Maui that indicates that EPA does not expect that many such discharges will be the “functional equivalent” of a discharge from a point source into a water of the United States. EPA’s addition of an eighth factor for assessing functional equivalence that was not discussed in Maui also seems designed to limit the situations in which a NPDES permit is required. EPA could use that “design and performance of the facility” factor as a flexible mechanism that would allow it to find that certain discharges to groundwater are not covered by the Clean Water Act even if they ultimately reach a water of the United States.

With the incoming Biden administration set to begin in a little more than a month, it is unclear if the draft guidance will be finalized or might be rescinded. The incoming administration is likely to have different priorities and may favor a broader view of the Clean Water Act that would regulate discharges into groundwater more expansively. If EPA finalizes the draft guidance, it could spur a new round of litigation over how the Clean Water Act applies to discharges into groundwater. Indeed, if finalized in its current form, it seems likely the draft guidance will be challenged by environmental groups or states that favor a broader regulation of groundwater.

Contacts

If you have any questions or would like more information on the issues discussed in this LawFlash, please contact any of the following Morgan Lewis lawyers:

Washington, DC
Duke K. McCall, III
Douglas Hastings
Drew Clearly Jordan

San Francisco
Ella Foley Gannon

Los Angeles
James Dragna
Rick Rothman

Philadelphia
Jeffrey Hurwitz

Princeton
John McGahren
Stephanie R. Feingold
Christopher McAuliffe