General Information:
In Iowa, local boards of health have primary responsibility for regulation of onsite wastewater treatment systems (also known as a private sewage disposal systems) serving 4 homes or fewer or less than 15 people, while the Iowa DNR has primary responsibility for larger (public) systems. In conducting their activities, counties must comply with the minimum state standards developed by the Iowa DNR. If counties fail to adopt or enforce state standards for smaller systems, the Iowa DNR has concurrent authority to require compliance with the minimum standards for onsite wastewater treatment and disposal.
Chapter 69 of the Iowa DNR administrative rules regarding onsite systems specify sitting and construction requirements relative to the primary and secondary treatment portions of sewage disposal systems, minimum depth to groundwater, minimum separation distances to potable water sources, and maximum percolation rates for soils. The rules provide design criteria for each alternative type of secondary treatment system. Counties have the authority to allow alternative or innovative performance based systems.
Licensing and Certification:
The Iowa DNR certifies time of transfer septic system inspectors for inspections at the time of sale for buildings with private sewage systems. For more information on time of transfer inspectors and certification, please see the Time of Transfer webpage.
In addition, the Iowa DNR is responsible for licensing commercial septic tank pumpers and cleaners. For more information on septic tank pumper and cleaner licensing, please see the Septic Tank Pumping webpage. The county boards of health are responsible for enforcement of the septic regulations and inspections.
General Permit #4:
Any onsite wastewater treatment system that discharges treated wastewater to a designated water of the state or a subsurface drainage tile must be monitored to ensure that it meets secondary treatment standards. To achieve these standards, all surface-discharging onsite systems must obtain coverage under NPDES General Permit #4. For more information on the requirements, please see the General Permit #4 webpage.
Sanitarian Training:
Because of the responsibility the counties have in this area, the Iowa DNR provides an annual training for new county sanitarians. The Iowa DNR actively works with the counties to improve their enforcement programs and train their staff.
The Iowa DNR has partnered with Des Moines Area Community College (DMACC) to develop a training center and curriculum covering onsite (private) wastewater systems. The training is provided statewide at various locations at least 10 times annually and covers all topics related to onsite wastewater systems. The Onsite Wastewater Training Center of Iowa, located at the DMACC Ankeny campus, includes numerous displays of onsite wastewater technology. The training is designed for county sanitarians, septic system installers, pumpers, and designers, but it is open to everyone.
The Iowa Onsite Wastewater Association (IOWWA) also provides training opportunities and information regarding private septic systems in Iowa.
Onsite Funding:
Funding is available for loans to individuals to replace inadequate onsite sewer systems. Please see the following links for more information in individual septic system loans: State Revolving Fund OSWAP Loan Program and USDA Rural Development.
Iowa Administrative Code Chapters regarding septic systems and onsite wastewater:
The current septic and onsite wastewater rule chapters are listed below:
Chapter 68: Septic Tank Cleaners
Chapter 69: Onsite Wastewater Treatment and Disposal
Chapter 93: Onsite Wastewater Systems Assistance Program
The septic and onsite wastewater rules are being revised as part of the Executive Order 10 (EO10) process, which requires all state agencies to identify which administrative rule chapters will be retained or rescinded. More information on EO10 and draft revisions to the onsite wastewater rules (Group 7 of the proposed rules) is available on the Water Quality Rulemaking webpage.
The WQB is currently accepting comments on the proposed revisions to Chapter 69 for private sewage disposal systems (onsite systems), as noted on the Water Quality Rulemaking page (linked above). Please email comments and questions on the proposed changes to npdes.mail@dnr.iowa.gov. Comments are due by June 7, 2024.
Helpful Onsite Links:
Residential Onsite Wastewater Treatment Overview
Septic System Diagram
County Sanitarian List
US EPA: Septic Systems (Onsite/Decentralized)
DMACC Onsite Wastewater Training Center
Iowa Environmental Health Association
Chapter 69 Waiver Request Form
Sign up for Onsite Wastewater Updates