Onsite Wastewater Treatment Systems

Onsite wastewater treatment systems (OWTS) are a fact of life for people who live in the country or in unincorporated areas. People who purchase or build a house in the country often do not realize what is involved with being a rural homeowner,particularly concerning sewage wastewater. Missouri State law RSMo701.025 701.059prohibits discharge of sewage onto the ground surface, into waterways, lakes or ponds (other than lagoons) or off the property that it serves.On August 28, 2004, RSMo 701.031was amended and now states any person installing OWTS shall be registered to do so by the Department of Health and Senior Services. You can find a list of Registered Installers at the following link:http://www.dhss.mo.gov/Onsite/counties/Saline.html

When there is less than 3 acres and is a single home or business, construction of new OWTS and major modification to existing systems requires an application fee, construction permit, a soil morphology test and approval from the Saline County Health Department. The permit may be obtained from the Saline County Health Department. A DHSS certified soil scientist should analyze the soil properties,which are critical in determining the appropriate design of the OWTS. Where conventional soil absorption systems and lagoons are not suitable, a registered engineer must design the OWTS. You can find a list of soil scientists at the following link:


The Missouri Department of Natural Resources(MDNR) permits facilities that have greater than three thousand gallons of wastewater daily flow or that produce other than “basically domestic” wastewater. In addition, the MDNR regulates all above ground OWTS (lagoons) for properties other than single-family residences.

Developers of subdivisions, mobile home parks, and campgrounds need to be aware of revised regulations governing the selection of OWTS and allowable lot sizes. On March 30, 1999, Missouri revised 10CSR 20 6.030 (Disposal of Wastewater in Residential Housing Developments). Under the revised regulations, developments consisting of seven or more lots that are less than five (5) acres require the MDNR’s approval of the wastewater treatment system before home construction or the sale of any lots.  For information on MDNR permitted facilities contact the Northeast Regional office at 660-385-8000

If you have any questions or need to register as an installer please contact the Saline County Health Department at660-886-3434 or MO Onsite Sewage Program at              573-751-6095

More information may be obtained from the Missouri Department of Health & Senior Services link at: www.dhss.mo.gov/Onsite/