The National Pollutant Discharge Elimination System (NPDES) permitting program requires all facilities that discharge pollutants from a point source into waters to obtain an NPDES permit. The permit defines what the facility is allowed to discharge and under what circumstances it can discharge it. A permit is a license to discharge pollutants.

Facility is a distinct real property that exists at a specific location (such as a man made structure and its surrounding real estate).

A Permitted Feature is the component of a Permit that describes the point from which pollutants are discharged from a Facility into its receiving waters