On September 24, 2018, in two separate decisions, the Sixth Circuit Court of Appeals found that coal ash wastewater that enters groundwater and eventually travels to navigable waters through the groundwater is not regulated under the Clean Water Act (“CWA,” or the “Act”). In these decisions, the Sixth Circuit expressly disagrees with recent holdings from the Fourth and Ninth Circuits, paving the way for potential Supreme Court review.
The CWA requires a permit for discharge of pollutants into navigable waters. 33 U.S.C. §§ 1251 et seq. At issue in both Sixth Circuit cases is whether the CWA extends to regulate indirect discharge into a navigable water, through groundwater. Rejecting the “hydrological connection” theory, the Sixth Circuit found that groundwater is not subject to regulation under the CWA because it is not a point source. Therefore, the discharge of pollutants into groundwater, and subsequent travel to a navigable water, also does not fall within the scope of the CWA.