As authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program controls water pollution by regulating point sources that discharge pollutants into waters of the United States. This program includes the U.S. Environmental Protection Agency's (EPA) Concentrated Animal Feeding Operations (CAFO) rule.
In Iowa, EPA delegates enforcement of the NPDES program to the DNR. The DNR's NPDES section issues NPDES permits and storm water permits to animal feeding operations and provides technical assistance to animal feeding operation owners and operators.
The EPA rules and rule history are available on its