Boone County, MO Septic Rules: What Homeowners Need to Know
Informational guide only. We don't issue permits or do septic work. Rules change, so confirm anything important with Boone County Resource Management.
Who Regulates Septic in Boone County
Boone County Resource Management says the County Commission adopted the county's onsite wastewater ordinance in 1993. For years, Columbia/Boone County Public Health and Human Services enforced it. On June 28, 2022, that responsibility moved to Boone County Resource Management. The City of Columbia's site now points onsite wastewater questions to the county. If you're looking for a system's history or want to understand the rules for your property, Boone County Resource Management's onsite wastewater page is the place to start.
The county notes that its design criteria follow statewide standards. The Missouri Department of Health and Senior Services sets those, and the state Department of Natural Resources handles larger systems over 3,000 gallons per day and lagoons serving more than a single-family home.
Why Boone County Soils Matter
The county's homeowner guide says a large portion of Boone County soils contain high levels of clay, which won't let wastewater percolate. It also names perched water tables as one of the most common limiting features. That's water held above a tight soil layer, and it can saturate a field from below. Some areas, such as windblown soils near the Missouri River bottoms and alluvial soils in creek floodplains, can suit conventional fields. Much of the county can't. That's why lagoons and engineer-designed systems are so common here.
Karst and Sinkhole Areas
Parts of Boone County have karst features: fractured or soluble limestone with caves, sinkholes and springs, where surface water can reach groundwater directly. Boone County's current lagoon requirements (updated 2022) list a 500-foot setback between a lagoon and any sinkhole, and require an engineer-designed and certified system in a designated sinkhole area. The 500-foot lagoon setback is also in Missouri's statewide setback table (19 CSR 20-3.060, Table 1).
Living Near Hinkson and Perche Creeks
The City of Columbia's watersheds page calls Hinkson Creek the city's largest watershed: about 26 miles long, starting east of Hallsville and running southwest through Columbia to join Perche Creek in southwest Columbia. Homes on septic near these streams sit where wastewater, stormwater and stream health meet. Keeping a system maintained is part of protecting them.
Routine Care Every Owner Should Know
From Boone County's homeowner guide (2011, archived on como.gov):
- Pump the tank every 3 to 5 years, depending on household size. A garbage disposal adds sludge.
- Clean the effluent filter about every 6 months.
- Don't use additives. Some can promote clogging.
- Spread out water use. Fix leaks, and don't do all the laundry in one day.
- Keep vehicles off the field, and keep surface water away from it.
- Lagoons: mow the banks, keep trees cleared, and keep the fence and gate in good repair.
- Keep a service record.
Read more about septic tank pumping.
Selling a Home: What Missouri Requires
State law doesn't require a septic inspection before a sale. If a lender or buyer asks for one, it must be done by an inspector or evaluator who meets Missouri DHSS requirements under 19 CSR 20-3.070. Boone County's own existing-system evaluation is for additions and remodels, not sales. Read more about septic inspections.
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