Since January 1, 1996, On-site Wastewater Disposal System Permits have been required by the State of Missouri. These include any new systems and major repairs to existing systems on all single-family dwellings on less than three (3) contiguous, deeded acres, as well as all multiple-family dwellings, businesses, and public buildings, regardless of acreage. (Any sub-divisions consisting of more than 6 lots will need to contact the Missouri Department of Natural Resources for further information and regulations.)

As each on-site wastewater disposal system is site specific, an individual application form, fee, soil morphology test, and site evaluation is required prior to the issuance of a permit to construct a new system or perform major repairs on an existing system. The installation of these systems must be done by a Registered Installer with current State of Missouri registration status. An exemption does exist for a private homeowner to install his/her own permitted system, for their personal dwelling only, following all State of Missouri regulations, requirements, and permitting criteria.