The Clean Water Act broadly divides sources of pollution into two categories, point-source pollution and nonpoint-source pollution. Sources of point-source pollution are regulated in the Clean Water Act through the National Pollutant Discharge Elimination System, or NPDES. In this lesson, you’ll learn about the permitting system under the NPDES, including when the process is triggered and effluent limitations.

The NPDES permit program issues permits that adapt the general goals of the Clean...