Resources

DHSS Resources

DHSS Inspector Resources

DHSS OSE Resources

Only Registered OWTS Onsite Soil Evaluators (OSE) can conduct site/soil evaluations for OWTS design using the forms below or similar forms.

Outside Resources

Missouri Laws Governing Onsite Wastewater Treatment and Disposal

A bill passed by the Missouri General Assembly and signed into law by the Governor in August 1994 addresses the protection of Missouri's groundwater (the source of much of our drinking water) and the prevention of the spread of disease organisms. The law governs sewage systems that treat and disperse wastewater, generally on the lot where it was produced - onsite systems.

The onsite sewage law covers soil absorption systems serving single or multiple residences or businesses with domestic wastewater flows of 3000 gallons per day or less and lagoons serving a single residence. The Missouri Department of Natural Resources (DNR) regulates all other sewage lagoons and sewage treatment facilities with daily flows of more than 3000 gallons, including public sewer systems. Anyone subdividing or developing property must comply with DNR residential development regulations as well as the onsite sewage law.

Under the law, the Department of Health and Senior Services (DHSS) has developed minimum standards for the size and location of sewage tanks and soil absorption trenches. County or city governments may adopt the state standards or stricter standards by ordinance.

Also under the law, DHSS lists persons who may conduct percolation tests and those who may conduct soils morphology evaluations for the design of onsite systems. In addition, DHSS provides training and registration for onsite system installers and licenses individuals to inspect or evaluate existing onsite sewage systems related to a real estate sale.

When a neighbor or other aggrieved person lodges a complaint about a failing system, the law provides for an investigation. If the system presents a nuisance or a health hazard, the nuisance must be abated. Major repairs, as well as new systems, must comply with minimum standards.

Missouri Regulations Governing Onsite Wastewater Treatment Systems

Missouri Department of Health and Senior Services' (DHSS) rules governing onsite sewage systems cover minimum construction requirements, system inspections at the time of property sales, and requirements for percolation testers and soil evaluators. These rules became effective in January 1996.
In just under one half of Missouri counties, the Local Public Health Agency, or DHSS staff, regulate new system construction and existing system repairs according to state standards. The state standards establish minimum requirements for the size and type of an onsite system based on an evaluation of the site and soil conditions. In the remaining counties and some cities, either the state construction standards, or more stringent local standards, have been adopted by ordinance. In those areas the authority for onsite sewage may be the Local Public Health Agency or another agency, such as a sewer district. To determine what type of authority governs onsite sewage in a county, check this Missouri Map.

Unless the property is exempt based on its size, a construction permit is required before system installation can begin. Contact the local administrative authority to begin the permit process. The health department in your county can help you with the process or refer you to the proper agency.