On February 1, 2018, the Ninth Circuit ruled in Hawai’i Wildlife Fund v. City of Maui that contamination that is discharged into the ground and later escapes through groundwater migration into a navigable waterway requires a National Pollutant Discharge Elimination System (NPDES) permit.  The NPDES permit system, authorized under the Clean Water Act, is mostly known for permits that regulate “point sources,” such as pipes, that discharge into navigable waters.  This new case finds that the Clean Water Act also covers some indirect discharges of pollutants into navigable waters.  This might include discharges into wells, infiltration ponds, or other repositories that connect with or drain to groundwater. Without a permit, such dischargers may now be exposed to agency enforcement or citizen suits by third party groups. 

The Environmental Protection Agency is now taking comments on a rule that would clarify the scope of the NPDES permitting program. Specifically, the EPA is requesting comments on whether or how it should regulate pollutants that enter navigable waters by way of groundwater or other subsurface flow. The notice of this proposed rule can be found here, and comments are due May 21, 2018.