NPDES Wastewater Permitting

The NPDES Section of the Iowa Department of Natural Resources issues discharge permits under delegation of a federal program known as the NPDES (National Pollutant Discharge Elimination System) permit program.  The NPDES program regulates the direct discharge of wastewater to surface waters.  The authority to issue NPDES permits rests either with a state or with the U.S. Environmental Protection Agency (EPA).

NPDES Program
+ NPDES Program Basics

waste water treatment

States gain approval to administer the NPDES program by demonstrating their program meets federal requirements.  Iowa was delegated NPDES authority by EPA in 1978.

Under Iowa's NPDES program, all facilities that discharge pollutants from any point source into surface waters are required to obtain an NPDES or operation permit from the Iowa DNR. The permits require compliance with all federal standards, state rules, and state administrative code.

A pollutant includes any type of industrial, municipal, and agricultural waste discharged into water. Pollutants can enter waters by many pathways including agricultural, domestic, and industrial sources.  These sources are generally categorized as either point sources or non-point sources.

Point source discharges include discharges from publicly owned treatment works (POTWs), discharges from industrial facilities, and discharges of urban runoff. While provisions of the NPDES Program do address certain agricultural activities, most agricultural facilities are defined as non-point sources and are exempt from NPDES regulation.

Pollutant contributions may come from both direct and indirect point sources.  Direct point sources discharge wastewater directly to a surface water, whereas indirect point sources discharge wastewater to a POTW, which in turn discharges directly to surface waters.

POTWs are direct dischargers and they must obtain an NPDES permit. If the amount of pollutants leaving a POTW is too high, or the discharge endangers public health or the environment, the facility may violate its permit and can be fined or required to upgrade. A POTW may have trouble meeting its NPDES permit conditions if there are too many pollutants in the wastewater flowing into the treatment plant. One way to reduce pollutants in influent wastewater is to require industrial pretreatment. Some larger cities in Iowa administer local pretreatment programs that regulate industrial discharges in their city.

Industries, businesses, and other privately-owned facilities that discharge directly to surface waters must also obtain an NPDES permit. Industries who discharge wastewater to a POTW may be required to have a treatment agreement with the POTW. The NPDES Section reviews treatment agreements for conformance to federal and state pretreatment requirements.

To read more about wastewater, please view the following article from the Iowa Conservationist: Down the Drain: What Happens to Our Wastewater?


+ Types of NPDES Permits
+ Major Components of an NPDES Permit
+ Development of an Individual NPDES Permit
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Proposed General Permits for Hydrostatic Testing and Dewatering: 

The NPDES Section has proposed two new general permits for rulemaking. Proposed General Permit #8 will be for Hydrostatic Testing, Tank Ballasting, and Water Lines. Proposed General Permit #9 will be for Dewatering Activities and Residential Geothermal Discharges. Public hearings on the Notice of Intended Action for the proposed permits will be held in March of 2018. For more information and drafts of the general permits, please refer to the NPDES General Permit #8 and the NPDES General Permit #9 webpages.

Disadvantaged Communities: 
For more information on how a community or entity may qualify as disadvantaged, please see the Rural Community Sewers page.