The NPDES Permits Section issues discharge or operation permits under delegation of the 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. Under this program, industrial facilities and POTWs (publicly owned treatment works) must receive a NPDES permit before discharging wastewater directly to surface waters. The permits require compliance with all federal standards and may also require additional controls based on local conditions.

Because POTWs are direct dischargers, they must obtain and comply with a NPDES permit. This permit limits the amount of pollutants the sewage treatment plant may discharge. If the concentration of pollutants is too high, or if its discharges endanger 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 the amounts of pollutants in the influent wastewater is to require pretreatment. Thus, the conditions of a POTW's discharge permit might dictate the need for pretreatment.

Industries that discharge wastewater to a municipal sewer system may be required to have a treatment agreement. The NPDES Permits Section reviews treatment agreements for conformance to federal and state pretreatment requirements. Some larger cities have accepted responsibility for administering local pretreatment programs.

The authority to issue NPDES permits in a given state rests either with the state's environmental agency or with the U.S. Environmental Protection Agency. States can gain approval to administer the NPDES program by demonstrating that their state program meets all federal requirements. Iowa was delegated authority to administer the NPDES program by the EPA in 1978.

In recent years, the DNR has begun permitting discharges of stormwater as part of the Clean Water Act. In many cases, stormwater permits are covered by common conditions and do not require extensive individual review.

In Iowa, local (county) boards of health have primary responsibility for regulation of sewer systems serving less than 15 people, while the DNR has primary responsibility for larger (public) systems. Counties must comply with the minimum state standards developed by the DNR. If counties fail to adopt or enforce the DNR standards for smaller systems, the DNR has concurrent authority to force compliance by individuals and the counties with the minimum standards for on-site wastewater treatment and disposal.

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