In Sierra Club v. Virginia Electric & Power Company, ___ F.3d ___, No. 17-1562, No. 2018 WL 4343513 (4th Cir. Sep. 12, 2018), the Fourth Circuit held that coal ash settling ponds are not “point sources” under the Clean Water Act which prohibits discharging pollutants into regulated waters from a “point source” without a National Pollutant Discharge Elimination System (“NPDES”) permit. Id. at *2. The court held that the “point source” requirement was not satisfied by the “simple causal link” created when pollutants leach into groundwater from settling ponds and then flow into regulated navigable waters. Id. at *5.

The court reversed a district court decision that would have expanded the scope of the Clean Water Act and subjected any facility, industrial or otherwise, that inadvertently concentrates or stores pollutants in an unlined surface impoundment to NPDES permitting. Under that approach, if groundwater conveyed pollutants from lakes, farm fields, or other passive physical structures, those facilities would require an NPDES permit if the groundwater beneath them was connected to navigable waters.

The Fourth Circuit’s analysis made an important distinction between passive facilities and those that actively discharge pollutants. The court held that a “point source,” must “function[] as a conveyance of the pollutant into navigable waters.” Id. at *7. Simultaneously, the court emphasized that diffuse seepage of water through ponds and into groundwater does not amount to a conveyance. Id. Therefore, unlined surface impoundments that contain or manage pollutants, but are not designed to convey pollutants into groundwater, are outside the purview of the NPDES permitting requirement.

Ash settling ponds and other unlined surface impoundments are of course still regulated under the Resource Conservation and Recovery Act.