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.  For more information on the Iowa DNR's NPDES Program, please see the discussion below.

NPDES Program
+ NPDES Program Basics

The NPDES Section of the Iowa DNR issues discharge permits under delegation of the federal 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 in each state rests either with the state's environmental agency or with the U.S. Environmental Protection Agency (EPA).  States can gain approval to administer the NPDES program by demonstrating that their state program meets all the federal requirements.  Iowa was delegated authority to administer the NPDES program by the EPA in 1978.

Under Iowa's NPDES program, all facilities that discharge pollutants from any point source into waters of the United States or waters of the state are required to obtain an NPDES or operation permit.  The permits require compliance with all federal and state standards and may require additional controls based on local conditions.

The term pollutant is defined very broadly and includes any type of industrial, municipal, and agricultural waste discharged into water.  Pollutants can enter waters from a variety of pathways including agricultural, domestic, and industrial sources.  For regulatory purposes, these sources are generally categorized as either point sources or non-point sources.  Typical point source discharges include those from publicly owned treatment works (POTWs), from industrial facilities, and from urban runoff.  While provisions of the NPDES Program do address certain specific types of 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 sources.  Direct sources discharge wastewater directly into a receiving waterbody, whereas indirect sources discharge wastewater to a POTW, which in turn discharges into a receiving waterbody.

Because POTWs are direct dischargers, they must obtain and comply with a NPDES permit.  If the concentration of pollutants leaving a POTW is too high, or if discharges from a POTW dendanger public health or the environment, the facility violates its permit and can be fined and/or forced to upgrade its operation.  A POTW may have trouble meeting its NPDES permit conditions if the amounts of pollutants in the wastewater flowing into the treatment plant (the influent wastewater) are too high.  One way to reduce pollutants in influent wastewater is to require pretreatment.  Thus, the conditions of a POTW's permit might dictate the need for pretreatment.

Industries that are direct dischargers to surface waters must also obtain and comply with a NPDES permit.  Industries who discharge wastewater to a municipal sewer system may be required to have a treatment agreement.  The NPDES Section reviews treatment agreements for conformance to federal and state pretreatment requirements.  Some larger cities have accepted responsibility for administering local pretreatment programs that regulate industrial discharges in their community.

To read more about wastewater, please view the following article from the Iowa Conservationist: Down the Drain: What Happens to Our Wastewater?  (*.pdf file)

+ Types of NPDES Permits
+ Major Components of a Permit
Hot Topics

General Permit #5 Renewal:

The NPDES Section is currently drafting a renewal of General Permit 5 (GP5) for Mining and Processing Facilities. Please see the General Permit 5 webpage for more information.

Pesticides General Permit (GP #7):

The NPDES Section is currently drafting a renewal of the Pesticides General Permit (PGP, or GP7). Please see the General Permit 7 webpage for more information.

General Permit #6 Renewal:

The NPDES General Permit for Well Construction and Well Service Discharges (GP6) has been renewed. The new permit will be effective on March 1, 2020. Please see the General Permit 6 webpage for more information.

New Chloride Fact Sheet:

A new fact sheet is available on Chloride WQS. Please follow the link to obtain guidance on the chloride water quality standards (WQS) and chloride compliance options.

General Permits for Hydrostatic Testing and Dewatering:

The NPDES Section issued two new general permits on July 1, 2018. General Permit #8 is for Hydrostatic Testing, Tank Ballasting, and Water Lines and General Permit #9 is for Dewatering Activities and Residential Geothermal Discharges. For more information, 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.