Homes in portions of Adair County that are without public sewer systems rely on onsite wastewater treatment systems (OWTS) to treat wastewater and disperse the treated effluent on the property where it originates.  These systems should be designed and operated to prevent human contact with sewage and to prevent the contamination of surface water and groundwater.  The Missouri Onsite Sewage Law (701.025-701.059 RSMo) and associated rules establish minimum standards for construction of onsite sewage treatment systems.

A permit is required for construction of an OWTS if the property is smaller than three acres, or if it is adjacent to a public utility lake or Corp of Engineers property. Due to the recent change in onsite program authority, to obtain a permit, you should now contact the Missouri Department of Health and Senior Services at 573-751-6095.

If the property does not meet conditions that would require a permit, the following conditions must be met:

  1. All points of the system must be at least 10 feet from the property line, and
  2. No effluent enters adjoining property, and
  3. No effluent contaminates ground water or surface water, and
  4. It does not create a nuisance. Nuisance  is defined as human waste discharged or exposed on land in a manner that makes it a potential instrument or medium for breeding of flies and mosquitoes, the production of odors, or transmission of disease.

Regardless of whether a permit is required, the law requires that any person installing a new OWTS, or repairing an existing OWTS, be registered to do so with the Department of Health and Senior Services. Find a list of the registered installers in Missouri.

New OWTS are designed based on the proposed home and the soil conditions on the site. Therefore, a soil morphology report, prepared by a Registered Onsite Soil Evaluator, should be prepared. The report determines the type of system and location on your property where the system may be installed. Find a list of the registered soil evaluators in Missouri.

Many times during a real estate transaction, the buyer or lending institution will require an inspection of the OWTS to determine if it is adequate and complies with the law. This inspection must be conducted by a person who is licensed to inspect or evaluate onsite systems. Find a list of Licensed Onsite System Inspectors/Evaluators.

If you have questions concerning onsite sewage treatment systems, please contact the Missouri Department of Health and Senior Services at 573-751-6095.