An onsite wastewater treatment system treats wastewater and disperses it on the property where it is generated.  They prevent human contact with sewage and prevent contamination of surface and groundwater. 

The Missouri Department of Health and Senior Services has set minimum requirements for onsite wastewater systems to be compliant, including for starting new systems and major changes to existing systems.  

You can find more information on the Missouri DHSS website, including: 

Find a registered professional

Become Registered/Licensed

Apply for a Permit

File a Complaint

Missouri Onsite Wastewater Treatment System Owner's Manual 

Onsite Sewage Laws & Rules Reference Manual