Building permits, zoning and land rules in Montgomery County, Missouri

Yes, with exceptions. Unincorporated Montgomery County requires a construction permit for structures 10-by-10 feet or larger, while agricultural buildings, fences, decks and porches are exempt¹. The official Planning and Zoning page provides a construction application¹. Missouri leaves fire and building-code adoption to local governments, so a county construction permit should not be mistaken for proof that one uniform statewide residential code controls the project⁶.

Montgomery County's construction permit is described as a land-use or health-related permit rather than enforcement of an adopted residential code¹. We could not confirm the current inspection sequence, certificate-of-occupancy requirement, fees, or a general owner-builder exemption; ask Planning and Zoning for the rules tied to the parcel and proposed structure before ordering plans or materials^1,4.

Montgomery County Planning and Zoning is the starting office for county planning, zoning and construction applications¹. The office is at 310 Salisbury St., Ste. D, Montgomery City, MO 63361, and lists 573-564-2142 and planningzoning@mcmo.us¹. The county page lists in-house office hours from 8 a.m. to 4 p.m., Monday through Friday, and links a construction application¹.

Ask the office to identify the parcel's jurisdiction and zoning district before treating the county answer as final, because incorporated places can have their own rules and Missouri county zoning authority concerns unincorporated territory⁷. Ask what drawings, site-plan details, approvals, fees and inspections apply to the exact project; a complete current county permit process could not be confirmed¹.

Yes. Montgomery County applies zoning, while Missouri law allows qualifying counties to adopt zoning for unincorporated territory after voter approval^1,7. The practical answer for a buyer is parcel-specific: ask Planning and Zoning to identify the district and confirm the current use, setback, lot-size, height and accessory-structure rules in writing¹.

The county's zoning appears to set setbacks of 50 feet front and rear and 25 feet on the side in the AGR zone, and 30 feet front and rear and 15 feet on the side in the RES zone¹. We could not confirm current ordinance text for minimum dwelling size, minimum lot size or lot coverage¹. We also could not confirm a county rule that specifically authorizes residential RV use, tiny-home occupancy, manufactured-home occupancy or an accessory dwelling¹. Missouri's farm-structure protection concerns county fire-protection and fire-prevention ordinances; it is not a blanket exemption from zoning, septic, floodplain or other land-use requirements⁸.

The Montgomery County Health Department reviews onsite sewage permit applications under the county sewer ordinance⁵. Most onsite wastewater installations and repairs require a construction permit, although some single-family residential lots may qualify for an exemption that must be confirmed before work starts³. The health department tells the homeowner or installer to complete the septic application packet and submit it for review⁵.

The county health page lists a $165 onsite sewage permit fee, while the state says application fees were temporarily suspended effective August 28, 2026; ask the health department which charge currently applies before paying^3,5. For residential property under three acres the state requires a permit, and the exemption does not apply in some counties, so ask the health department whether a larger tract qualifies³. Only 0.2% of mapped county soils avoid a “very limited” rating for conventional septic drain fields, so make septic feasibility an early contingency rather than assuming a standard field will work⁹. Property owners who want to install their own septic system must attend a class and pass the DHSS test⁵.

We could not confirm a Montgomery County rule that specifically allows long-term RV living, temporary camping or tiny-home occupancy on private land¹. County zoning and the construction-permit requirement still make Planning and Zoning the right office to ask before buying a parcel for either use¹. Ask whether the proposed unit is treated as a dwelling, mobile home, recreational vehicle or accessory structure, and whether the parcel's district permits that use¹.

An off-grid plan does not remove wastewater obligations: Missouri generally requires approval before installing or repairing most onsite systems, and wastewater may not be discharged into a road ditch or onto the ground¹⁰. If a tiny home or RV will produce domestic sewage, get a written answer from the Montgomery County Health Department about the proposed sanitation setup before site work².

1. Confirm whether the parcel is inside a municipality or in unincorporated Montgomery County, because county zoning authority applies to unincorporated territory⁷.
2. Ask Montgomery County Planning and Zoning to identify the district and current construction-permit requirements, then obtain the county construction application¹.
3. Have the Montgomery County Health Department review onsite sewage feasibility and determine whether a permit or exemption applies before installation or repair begins³.
4. Budget for a site-specific wastewater design because only 0.2% of mapped soils avoid severe limitations for a conventional drain field⁹.
5. If access connects to a state highway, obtain the required MoDOT right-of-way permit and contact the Traffic Specialist at least 48 hours before work begins^11,12.
6. Confirm inspections and any occupancy approval directly with Planning and Zoning because those county steps could not be verified¹.

Start with buildability, wastewater and access rather than the listing description. County zoning and a construction-permit requirement apply, but current district standards and permit details should be confirmed for the parcel with Planning and Zoning¹. Septic deserves special attention because only 0.2% of mapped soils avoid severe limitations for a conventional drain field⁹.

Check whether the driveway enters a state highway, because work in MoDOT right-of-way requires a permit¹¹. Ask the relevant jurisdiction whether the building site lies in a regulated flood hazard area; some participating Missouri jurisdictions restrict projects in designated floodplains¹³. For purchase budgeting, the county's effective property-tax rate is about 0.7%, and the median annual property-tax bill is $1,282⁹. Missouri does not require a septic inspection before a property sale, but a lender or buyer may ask for one and some counties require it, so ask the health department¹⁰. Private-well permitting was not confirmed, but the Montgomery County Health Department provides well-water testing services⁵.