Building permits, zoning and septic rules in Boone County, Missouri

Yes. Unincorporated Boone County requires a building permit for work that adds or physically changes structures, including dwellings, garages, carports, sheds, pole barns, manufactured homes, additions, remodeling and regulated electrical, plumbing, roofing, gas and HVAC work; cosmetic work does not require one¹. Boone County does not require a demolition permit, although controlled burning and asbestos removal may involve other agencies¹. County applications receive land-use, floodplain and address review, followed by inspections during construction^2,10.

County-issued permits are subject to the adopted 2015 International Codes¹⁰. A structure that passes code review receives a Certificate of Occupancy, and the county says processing takes three business days². Missouri's farm-structure exemption is narrow: it limits county fire-protection ordinances and does not create a blanket exemption from Boone County zoning, building, floodplain or septic requirements¹¹.

Boone County Resource Management is the building-permit and inspection office for areas outside Columbia city limits^2,10. Its main number is (573) 886-4330, its email is resmgt@boonemo.gov, and its office is in the Boone County Government Center at 801 E Walnut, Rm. 315, Columbia, MO 65201-7732². The office listing above links to the county's online application portal².

Inside Centralia, building permit applications go to the City Administrator instead⁴. For any other city or town, the county says that zoning and building-permit questions go to the city where the property lies¹.

New-construction fees are based on square footage, while alteration and remodeling fees are based on estimated construction cost; wastewater and driveway fees may be added¹. The current schedule sets a $40 non-commercial minimum and a $70 commercial minimum, doubles the fee for construction started without a permit, and expires permits after 180 days of inactivity¹². Credit-card payments add 2.35%, with a $1.55 minimum¹².

Yes, in unincorporated areas. Boone County administers zoning there, but incorporated cities and towns administer their own zoning and land-use rules, and the county has no jurisdiction inside them^1,7. Centralia, for one, publishes its own zoning chapter⁵. Permitted uses, setbacks and building heights depend on the county zoning district⁷.

Minimum lot area varies sharply by district: an A-1 lot requires 10 acres, an A-2 lot 2.5 acres, an A-R lot one-half acre, and an R-S or R-D single-family lot 7,000 square feet⁷. Divisions that leave lots or tracts under twenty acres trigger the county subdivision regulations⁷.

One accessory dwelling is allowed on a legally created parcel in the A-1, A-2, A-R and R-S districts, sharing ownership with the primary dwelling and capped at 75% of its size or 1,500 square feet, whichever is less¹³. A second county provision says an accessory dwelling needs a parcel of 20 acres or larger⁷. The two provisions conflict, so ask Resource Management which applies to your parcel before planning a second dwelling.

Boone County Resource Management administers on-site wastewater regulation and permitting countywide³. A permit is required for a new or renovated on-site sewage system, but a separate wastewater application is unnecessary when the owner applies simultaneously for a new-home building permit³. A county pre-site inspection takes place before construction or reconstruction, and the system must remain uncovered until final inspection³.

Only 1.3% of Boone County soils are rated without severe limits for a conventional drain field, so make wastewater feasibility and system cost purchase conditions rather than assuming a standard field will work¹⁴. Missouri requires a construction permit for most on-site systems, although some single-family lots may qualify for an exemption that does not apply everywhere¹⁵. Resource Management is the office to determine the parcel-specific permit path in Boone County³.

We could not confirm a general Boone County rule allowing or prohibiting residential or long-term RV occupancy on private land, or a categorical occupancy rule for tiny homes. The one RV rule we found applies to flood zones: in unincorporated Boone County, an RV on a site in A, AO, AE or AH flood zones must either stay fewer than 180 consecutive days while fully licensed and ready for highway use, or meet the permitting, elevating and anchoring requirements for manufactured homes⁸. Ready for highway use means the RV is on its wheels or jacking system, attached only by quick-disconnect utilities and security devices, and has no permanently attached additions⁸. Travel trailer parks are a conditional use only in the REC Recreation and C-G General Commercial districts¹³. Ask Resource Management about the parcel's zoning district and flood zone before buying.

Manufactured homes have a clearer rule. A manufactured home used as a dwelling must contain at least 650 square feet and is allowed where single-family dwellings are permitted, subject to district yard, density, parking, tie-down, skirting and wastewater rules⁷. In a recorded subdivision it needs conditional-use approval, and a placement permit is required before the home is placed⁷. For a tiny home, ask Resource Management how the ordinary dwelling rules apply.

1. Confirm whether the parcel is unincorporated, then identify its county zoning district and district-specific uses^1,7.
2. Verify legal lot status, minimum lot area, setbacks, height limits, floodplain status and whether subdivision review applies^7,16.
3. Submit the application and supporting site materials; new construction now requires an approved site and setback inspection before Boone County issues the building or on-site wastewater permit^17,18.
4. Arrange the wastewater pre-site inspection and keep the system uncovered through final inspection³.
5. Obtain a county driveway permit for a new driveway off a county-maintained road; a driveway on a state highway may involve MoDOT, and work in MoDOT right-of-way needs a state permit^1,6.
6. Pay the calculated fees, complete construction inspections and obtain the Certificate of Occupancy after code compliance^2,10,12.

Start with jurisdiction and zoning: county rules govern unincorporated land, while each incorporated city or town uses its own land-use system¹. Check the district, minimum lot area, legal lot status, setbacks and flood map before deciding where a house, driveway or accessory building can sit^7,16. Floodplain status matters too: building in the floodway is strictly prohibited, except for agricultural structures designed to let floodwater pass through, and floodplain-fringe structures must be elevated or floodproofed¹⁶. Confirm legal road access as well; a new driveway off a county-maintained road needs a county permit, which may also be needed to resurface a driveway or replace a culvert, while a driveway within state right-of-way needs MoDOT approval^1,6.

Missouri lets landowners drill their own well or install their own pump without a state well permit, though contractors need one; we could not confirm any Boone County well rule, so ask Resource Management¹⁹. Treat wastewater feasibility as a purchase condition because only 1.3% of county soils are rated without severe limits for a conventional drain field¹⁴. Ask Resource Management about the pre-site inspection before assuming the homesite works³. Boone County is 46.4% wooded and 82.1% of its land has slopes of 15% or less, but parcel-level clearing, drainage and grading can differ sharply¹⁴. The median property-tax bill is about $2,232 a year at an effective rate near 0.9%, useful context but not a parcel-specific quote¹⁴.