Private Sewage Disposal Systems
IAC 567 Chapters 64 and 69 | Last Updated May 2024
A private sewage disposal system is defined as “a system which provides for the treatment or disposal of domestic sewage from four or fewer dwelling units or the equivalent of less than 16 individuals on a continuing basis, including domestic waste, whether residential or nonresidential, but not including industrial waste of any flow rate except as provided for in IAC 567—68.11(455B)*. Private sewage disposal systems include, but are not limited to septic tanks, holding tanks for waste, chemical toilets, impervious vault toilets and portable toilets.”
*IAC 567-68.11(455B) addresses on-farm food processing wastewater.
General Requirements – Domestic Wastewater
Private Sewage Disposal Systems (as defined above) are regulated in accordance with county rules and Iowa Department of Natural Resources (IDNR) regulations contained in IAC 567 - Chapter 69. These regulations are available here.
Chapter 69 regulations state:
- No private sewage disposal system shall be installed or altered unless an applicable permit is applied for and issued by the IDNR or the local county health department (County Sanitarian). A list of county sanitarians is available here.
- No private sewage disposal system shall be installed, repaired, or rehabilitated where a publicly owned treatment works (POTW) is available (i.e., within 200 feet of a proposed building) or where a local ordinance requires connection to a POTW.
- No wastewater from private sewage disposal systems may be discharged to any ditch, stream, pond, lake, natural or artificial waterway, county drain tile, surface water drain tile, or land drain tile, to the groundwater, or to the surface of the ground. A properly designed and approved leach field is necessary.
- Private sewage disposal systems generally require inspection prior to transfer of property ownership. A list of IDNR approved system inspectors is available here.
More information on private sewage disposal systems is available here.
General Requirements – Industrial Wastewater
Iowa Administrative Code (IAC) 567- Chapter 69.8(1)d states: “Septic tanks shall not be used for the disposal of chemical wastes or grease in quantities which might be detrimental to the bacterial action in the tank or for the disposal of drainage from roof drains, foundation drains, or area drains”. IDNR interprets this rule to mean disposal of wastewater other than domestic sewage in a private sewage disposal system is prohibited. Therefore, wastewater from industrial processes, parts washing, vehicle/equipment washing, etc. may not be discharged to a private sewage disposal system.
EPA has additional regulatory requirements and restrictions on the disposal of industrial and commercial waste into private sewage disposal systems. Such a system is subject to EPA’s Underground Injection Control program requirements as a Class V injection well if it receives any industrial or commercial wastewater. Class V wells are a concern because they pose a risk to groundwater. Class V wells receiving motor vehicle wastewater (e.g., fluids from vehicle repair or maintenance activities) may be banned or need to meet new requirements. Information on federal defined Class V wells and motor vehicle waste disposal wells are available through the following EPA web sites.
Basic information about Class 5 Injection Wells
Motor Vehicle Waste Disposal Wells
Industrial or commercial wastewater disposal alternatives include: Connecting to a municipal sanitary sewage system; wastewater recycling and reuse; storage and transport to a municipal sanitary sewage system; storage and transport to a commercial waste management company; and evaporation. Each of these alternatives entails other regulatory requirements that should be fully understood and considered prior to implementation. Details on these regulatory requirements may be obtained by Contacting the IWRC.