Wastewater & NPDES Rules

General information

The Iowa Administrative Code (IAC) contains several chapters regulating the direct discharge of wastewater to waters of the state. The chapters containing most of the wastewater permit regulations are as follows:

• 567 IAC Chapter 60: Scope of Title - Definitions - Forms - Rules of Practice - definitions of terms in Chapters 60 through 69; wastewater engineering and NPDES forms; permit application requirements.
• 567 IAC Chapter 62: Effluent and Pretreatment Standards: Other Effluent Limits or Prohibitions - prohibited discharges; secondary treatment standards; federal effluent and pretreatment standards; reuse of treated effluent.
• 567 IAC Chapter 63: Monitoring, Analytical, and Reporting Requirements - pollutant test procedures; requirements for monitoring records, toxicity testing, and bypassing; monitoring tables; references the Supporting Document for Permit Monitoring Frequency Determination.
• 567 IAC Chapter 64: Wastewater Construction and Operation Permits - requirements for wastewater construction permits; requirements for operation, individual, storm water, and General Permits NPDES permits; public participation procedures; guidelines for completing a Notice of Intent for a General Permit; terms and conditions of permits; permit fees.
• 567 IAC Chapter 66: Pesticide Application to Waters - requirements for pesticide discharges to waters of the United States.
• 567 IAC Chapter 67: Standards for the Land Application of Sewage Sludge - sewage sludge requirements.

Rules regarding NPDES permits for Animal Feeding Operations (Chapter 65) can be found on the Animal Feeding Operations page. Rules regarding onsite (private) wastewater systems (Chapters 68, 69, and 93) can be found on the Private Septic Systems page. The Water Quality Standards (Chapter 61) can be found on the Water Quality Standards page.

The chapters above are regularly updated through the state's rulemaking process. Please refer to the Current NPDES Rulemaking Actions section below for more information on any proposed rule changes.

Current NPDES Rulemaking Actions

EO10 Rulemaking

Executive Order 10 (EO10) signed by the Governor on January 10, 2023, requires all state agencies to identify administrative rule chapters that will be retained or rescinded. The EO10 process for both the review of existing rule chapters and the reauthorization of rule chapters will include public engagement with the opportunity for meaningful input throughout the process. More information on the proposed changes to the wastewater rules that will be made as part of the EO10 process is available on the Water Quality Bureau Rulemaking webpage.

Past NPDES Rulemaking Actions

Renewal of NPDES General Permits

On August 16, 2022, the Environmental Protection Commission (EPC) adopted a rule change to Chapter 64 to renew five of Iowa’s NPDES general permits. The general permits cover certain wastewater discharges from mining and processing facilities (GP5), well construction activities (GP6), pesticide applications (GP7), hydrostatic testing, tank ballasting, and water lines (GP8), and dewatering activities and household geothermal systems (GP9). GPs 5, 6, and 7 were renewed at the same time in order to align the permit effective dates so that future renewal rule makings for these permits can be combined. Minimal changes were made to GPs 5, 6, and 7. GPs 8 and 9 were renewed because the current versions expired on June 30, 2023. The changes GPs 8 and 9 clarified existing requirements and addressed needs identified during the initial permit terms. General permits 5, 6, 7, 8, and 9 were effective as of July 1, 2023.

On November 15, 2022, the EPC adopted a final rule for Chapters 60 and 64 to renew four of Iowa’s NPDES general permits; three for storm water (GPs #1, #2, and #3) and one for private sewage disposal systems (GP #4). The revisions to GPs 1 through 4 and to Chapter 60 improved the clarity and readability of the requirements, definitions, and standard conditions. The revisions did not affect the substance of the general permits. General permits 1, 2, 3, and 4 were effective as of March 1, 2023.

For more information on the renewed general permits, please see the NPDES General Permits webpage.

Summary of Rulemaking Procedures

When the NPDES Section is considering a change to the wastewater rules, a draft rule package is developed and a public meeting is scheduled to gather initial stakeholder input on the draft rules. After the initial stakeholder comments are incorporated into the draft rules, the NPDES Section prepares an internal rulemaking package for review by DNR Legal staff and the Governor's Office. Once DNR Legal staff and the Governor's office have reviewed and approved the proposed rule, the rulemaking package is presented to the Iowa DNR Environmental Protection Commission (EPC) for approval as a Notice of Intended Action (NOIA). If approved by the EPC, it is published in the Iowa Administrative Bulletin (IAB) as an NOIA. Once the NOIA is published, the rule is discussed at the next legislative Administrative Rules Review Committee (ARRC) meeting. After a public comment period in which hearings are held and comments are accepted, the proposed rule is presented to the EPC for approval as a Final Rule. If a final rule is approved by the EPC, after consideration of public comments, it is published in the Administrative Bulletin as a Final Rule. The final rule will be presented to the ARRC after it is published and before it becomes effective. Please see the summary steps below:

Draft rule package prepared - Public meeting on draft rule - Comments incorporated into draft rule - DNR Legal review - Governor's Office review - NOIA presented to the EPC - NOIA publication in the IAB - ARRC review of NOIA - Public comment period - Responsiveness summary prepared - Final Rule presented to EPC - Final Rule publication in the IAB - ARRC review of Final Rule - Final Rule becomes effective