Functional equivalent of a direct discharge – Do discharges to ground water at your facility require an NPDES Permit?

The April 2020 Supreme Court of the United States (SCOTUS) decision in County of Maui v. Hawaii Wildlife Fund, 140 S. Ct. 1462 (Maui Decision) held that a National Pollutant Discharge Elimination System (NPDES) permit is required “when there is a direct discharge from a point source into navigable waters or when there is the functional equivalent of a direct discharge.” Specifically, the Maui decision determined that underground injection wells at a wastewater treatment plant on the Island of Maui, Hawaii, which discharged wastewater to groundwater that travels to the Pacific Ocean, needed an NPDES permit because the discharge is the functional equivalent of a direct discharge of pollutants to a water of the United States (WOTUS) (Pacific Ocean). In November 2023, the EPA released draft guidance to provide additional permitting considerations and direction for the implementation of the Maui decision in the NPDES permit program. The EPA’s draft guidance applies to point source discharges that reach a WOTUS via groundwater or other subsurface flow. EPA held a comment period for the draft guidance in November and December 2023. EPA’s next action to publish final guidance is expected at any time. Prior to the Maui decision, case law was divided on whether the Clean Water Act governs discharges into groundwater that is hydrologically connected to a WOTUS. The Maui decision was the first decision at the SCOTUS level to clarify that the scope of the NPDES permitting program includes some discharges through groundwater to surface waters. The Maui decision and forthcoming final guidance document will affect facilities that have potential functional equivalent discharges. Sugar beet facilities with discharges to groundwater from features such as unlined ponds, spray fields, or land application sites may need to conduct functional equivalent evaluations. This presentation will provide a brief regulatory background behind the Maui Decision, discuss the draft guidance (or final guidance, if this is released by the time of the presentation), potential implications to sugar beet facilities, and NPDES permitting precedence to date for the functional equivalent issue.