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System options are determined by a soil morphology evaluation conducted by an approved soil evaluator (view a list of approved soil evaluators). Alternative systems must be designed by a profession engineer licensed in the State of Missouri. Conventional systems are often designed in accordance with Private Sewage Disposal Code of St. Charles County by OWTS installers licensed with St. Charles County.
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A septic system was the primary system used for years to treat sanitary sewage. In the past 30-40 years, many new options for treatment of sewage were developed and allow for systems to be located in difficult areas and smaller locations. Septic systems are a type of OWTS, but they are no longer used.
A permit is required for the installation, modification, alteration, addition to, or repair of any OWTS that treats 3,000 gallons or less of waste per day.
St. Charles County utilizes the State of Missouri Department of Health and Senior Services “Green Book” for determining flow rates for sewage (specifically Table 4).
No. St. Charles County does not allow for the installation of new lagoons.
No. St. Charles County does not allow the surfacing of sewage regardless of property ownership.
Yes. Provided the site and the soil allow, St. Charles County allows all types of conventional and alternative systems (other than lagoons and wetlands) including gravel and pipe, gravelless, EPS gravelless, chamber, dosing, sand filter, peat/bio filter, mound, and subsurface drip distribution (SDD).
Maybe. Determining whether you can install a system depends on many factors. First, alternative systems, as determined by soil morphology, must be designed by a professional engineer and installed by a licensed OWTS installer. Soils suitable for a conventional system, as determined by soil morphology, may be installed by an owner/occupant of a residential property provided a level of competency is present (determined by testing or interviewing as necessary) and at the sole discretion of the Building Official.
A minimum of 3 acres is required for the installation of a new OWTS.
A minimum of 3 acres is required for the installation of a new Onsite Wastewater Treatment System (OWTS). Also, if a viable public sewer is within 200 feet of the property, you must connect to public sewer.