On November 6, the U.S. Supreme Court heard oral arguments in a case involving the County of Maui’s underground injection program, and whether or not discharges to groundwater should be subject to permitting under the National Pollutant Discharge Elimination System (NPDES), if such discharges originate from a point source and end up traveling to a jurisdictional surface water. In February 2018, the Ninth Circuit Court of Appeals held that the County of Maui’s injection of highly treated effluent into an underground aquifer violated the Clean Water Act because, even though the treated effluent was discharged into groundwater and not surface waters, it eventually made its way to surface waters through underground crevasses.

The implications for this ruling are far-reaching for water recycling utilities that rely on aquifer recharge for their water supply program and comply with existing control programs required by the Safe Drinking Water Act. The WateReuse Association joined with twelve other associations in submitting an Amicus Brief urging the Supreme Court to overturn the lower court’s decision. The court is expected to rule on the case, County of Maui v. Hawai’i Wildlife Fund, et al., sometime next year.