Closure of Septic Tank and Lagoon Systems 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 #: 12-039 Guidance Documents Revised: 9/21/22

Title 124 - Onsite Wastewater Treatment Systems requires that whenever the use of an onsite wastewater treatment system is discontinued following connection to a sanitary sewer or following condemnation or demolition of a building or property or due to the construction of another onsite wastewater treatment system, the system must be properly closed. In addition, any further use of the onsite wastewater treatment system for any purpose is prohibited.

One of the following two methods must be used for the closure of a septic tank or holding tank:
  • Pump and Fill Method - The tank is pumped of all liquids and solids and then filled with soil. The soil must be tamped completely so as to prevent voids which would occur as a result of settling; or
  • Pump and Remove Method - The tank is removed after being pumped of all liquids and solids and the void left from the tank removal is filled in with soil. The soil must be mounded to provide for future settling.
Note: Disinfectant or anti-bacterial products can be used to clean the tank as an optional step in preparing the tank for closure.
The following must be used for closure of a wastewater lagoon:
  • The lagoon is drained or allowed to evaporate until there is no liquid remaining;
  • The fence is removed and the settled solids and liner material at the bottom of the lagoon is scraped out and properly disposed; and
  • The lagoon area is leveled and filled with clean soil. The soil must be mounded over the lagoon area to provide for future settling and to prevent water from ponding.
Only a certified professional, a professional engineer, a registered environmental health specialist or a person under their direct supervision may engage in the closure of an onsite wastewater treatment system.