Temporary Modification Fact Sheet
This guidance document is advisory in nature but is binding on an agency until amended by such agency. A guidance document does not include internal procedural documents that only affect the internal operations of the agency and does not impose additional requirements or penalties on regulated parties or include confidential information or rules and regulations made in accordance with the Administrative Procedure Act. If you believe that this guidance document imposes additional requirements or penalties on regulated parties, you may request a review of the document.

Form #: 12-043 Guidance Documents Revised: 12/14/22

A temporary modification to a failed onsite wastewater treatment system may be performed without meeting the design requirements of Title 124 – Onsite Wastewater Treatment Systems if the modification is to prevent a surface discharge or reduce a threat to public health.


The temporary modification must be registered. A written description must accompany the registration which:
  • States that a temporary modification was made; and
  • Describes the problem that caused the discharge and the reason the temporary modification was made.


Use of a system with a temporary modification for more than four months without Department approval is prohibited.

Only a certified professional, a professional engineer, a registered environmental health specialist, or a person under their direct supervision, may engage in the inspection, pumping, siting, layout, construction, reconstruction, alteration, modification, repair, closure or otherwise changing of an onsite wastewater treatment system. “Direct supervision” means the person overseeing the work is physically present on the site where the work is being done and has control over, responsibility for, and professional knowledge of the work being done.