Maintenance of Septic Systems and Lagoons 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 #: 12-031 Guidance Documents Revised: 10/11/22

Septic system and lagoon maintenance is important to prevent system failure and possible contamination of the environment. Title 124 - Onsite Wastewater Treatment Systems requires the following maintenance activities be performed to ensure the proper and effective treatment of wastewater generated from dwelling and non-dwelling facility sources.

Septic Tanks

Regular inspections of the septic tank must be performed and arrangements made for the removal and disposal of septage from the tank.
  • The owner of a septic tank must have a Master or Journeyman Pumper, a professional engineer, or a registered environmental health specialist periodically inspect the septic tank and remove septage from the tank whenever the top of the sludge layer is less than 12 inches below the bottom of the outlet baffle or whenever the bottom of the scum layer is less than three inches above the bottom of the outlet baffle.
  • The pumping and disposal of domestic septage must be in accordance with Title 124. Other federal, state, or local rules and regulations may also apply.
Lagoons

A lagoon must be operated and maintained in the following manner:
  • The liquid level in a lagoon must be maintained at a minimum depth of two feet. Additional water must be added as necessary to maintain the two-foot minimum depth.
  • The lagoon must be operated to prevent the liquid level from encroaching on the one-foot freeboard requirement of the lagoon. Contact a certified Pumper to remove wastewater from the lagoon, as needed.
  • The lagoon area must be mowed to keep grass and other plants at six inches or less in height on the lagoon slopes and top of dike.
  • All lagoon dike surface areas from the design high operating waterline to the outside toe of the dike, and all other areas which were disturbed during construction, must also be seeded or sodded and the grass cover maintained to prevent soil erosion.

    • Short grasses, such as blue grass, are preferred and should be mowed frequently to prevent overhanging vegetation. Alfalfa and long rooted grasses or vegetation that might damage the integrity of the lagoon must not be allowed to grow on the side slopes of the lagoon.
    • Weeds, cattails, reeds, and other wetland plants must be removed by physical or chemical treatment as they emerge. Trees and brush must not be allowed to grow within the setback distances identified in Chapter 5 of Title 124.
Solids should be removed from the lagoon, as needed by a Master or Journeyman Pumper, a professional engineer, or a registered environmental health specialist and disposed in accordance with Title 124 and any federal, state, or local regulations.