Single-Level Homes & Barndominiums in Johnson County, Missouri

Building a Home on Rural Land in Johnson County: The Rules

Last verified October 2026 from Johnson County's official documents. Rules apply to unincorporated land outside city limits. Always confirm with the county before you build.

Johnson County has no county zoning, building code, building permit or inspections outside the Whiteman Air Force Base Zoning Area. Septic is strict: the county health department requires a permit, a soil morphology evaluation and, in most cases, at least 3 acres.

• Zoning and building permits: “At this time, Johnson County, Missouri, does not have planning and zoning regulations, building codes, building permits, inspections, or occupancy certificates for unincorporated areas, except for properties located within the Whiteman Air Force Base Zoning Area.”
• Septic: “Johnson County Community Health Services is responsible to administer regulations for the design, construction and major modification of all Onsite Wastewater Treatment Systems (OWTS). Permits are required for new construction or modifications to any OWTS.” The permit for a new system is $250 (fee schedule as of October 1, 2026).
• Soil test: “Soil morphology evaluations performed by a qualified soil evaluator in accordance with 19 CSR 20-3.080 shall be required for all new OWTS installations and major modifications.” (Health Code §3.2.5.15)
• Minimum lot on septic: “A parcel proposed for development utilizing an onsite wastewater treatment system shall contain a minimum of three (3) acres unless otherwise approved by the JCCHS in accordance with this section.” (Health Code §3.2.5.11)
• No 3-acre exemption: “This code does not allow an acreage exemption for the construction or major modification of an OWTS except as provided for in Section 3.2.6.1.” (Health Code §3.2.5.1)
• Installing your own septic: “A property owner constructing or performing major modification of an OWTS for his or her own residence upon his or her own property shall not be required to have an installer’s license.” (Health Code §3.2.5.9)
• Floodplain: “Flood Plain: State and federal regulations apply to building in flood plains. Flood plain maps and construction permits for flood hazard areas are available at the Assessor's Office (660-747-9822).” (County Commission letter on zoning, February 3, 2026)
• Frost footing depth: Johnson County has no adopted building code, so no county frost depth applies. Every DreamStart plan puts footings 36 in. below grade (our standard, not a county rule).

Who to call: Johnson County Commission, 300 N. Holden Street, Suite 203, Warrensburg, MO 64093 · 660-747-2112 · CountyCommissioners@jocomo.gov · Septic: Johnson County Community Health Services, 723 PCA Rd, Warrensburg, MO 64093 · (660) 747-6121 ext. 258

Official source: Johnson County, Missouri: Planning & Zoning · Johnson County Community Health Services: Onsite Wastewater Treatment Systems · Johnson County Code of Health Regulations (revised 7/30/2026) · County Commission letter on zoning (February 3, 2026)

Note: If your land is inside the Whiteman Air Force Base Zoning Area, zoning rules apply; the county's letter gives 660-463-7934 for that area.

No building code doesn't mean anything goes. Your plan should still meet a real standard, because your lender, your insurer and your family will care even if the county doesn't. Every DreamStart plan is designed to one.