Groundwater Discharge - U.S. Supreme Court May Decide Maui Case in 2020
The United States Supreme Court heard oral arguments on November 6, 2019, in County of Maui, Hawaii v. Hawaii Wildlife Fund, No. 18-260 (U.S.), and may issue a decision in 2020. The principal question at issue is whether the Clean Water Act’s regulation of discharges to the navigable “waters of the United States” extends to circumstances where the discharge is made to groundwater which ultimately reaches a navigable water of the United States.
The case arises from a citizen suit brought against the County of Maui for failing to obtain Clean Water Act permits for wastewater treatment plant discharges of treated wastewater to groundwater injection wells. It was undisputed that the treated wastewater, through the groundwater, ultimately reached the Pacific Ocean. The parties’ arguments rise and fall on the definition of “discharge” under the Clean Water Act, which “means … any addition of a pollutant to navigable waters from any point source,” 33 U.S.C. § 1362(12), and whether the effluent from the wastewater treatment plant is from any point source.
Having lost in the lower courts, Maui, joined by the United States Environmental Protection Agency, which issued a policy statement in April 2019 declaring that discharges to groundwater were excluded from the Clean Water Act’s definition of a point source discharge, argued that regulation of discharges to groundwater would be a vast overreach of the federal government. The citizen advocacy organizations argued that exempting these discharges would create a gaping regulatory loophole. As the Supreme Court Justices acknowledged throughout the oral argument, the decision, which could be rendered by June 2020, could have far-reaching impact on large and small dischargers across the country.