Off-Grid Living in Franklin County, Missouri

Franklin County is one of the Missouri counties that actually opted into countywide planning and zoning under the state's Chapter 64 RSMo enabling statute, and it has layered on its own building codes and a fresh onsite sewage ordinance. So if you're used to "no rules out here" Missouri counties, don't assume that applies here. I've dug through the county's official pages and the state health/DNR sites to sort out what's confirmed and what isn't.

Zoning: Franklin County's Planning & Zoning Department administers Unified Land-Use Regulations covering zoning districts, subdivisions, floodplain, and more, per the county's Master Plan developed under Section 64.815 RSMo. Whether raw land can simply be occupied depends on the district, so check with the county before you buy or move onto land.

Dwellings/tiny homes/RVs: This is genuinely murky. The county's regulations govern what dwelling types are allowed where, but I could not find an official county document spelling out tiny-home square footage minimums, ADU caps, or RV-residency rules. Ignore third-party "tiny home checklist" blogs claiming specific numbers for Franklin County, they're not sourced to the county. Call Planning & Zoning and ask them to check your specific parcel and district.

Building permits: The county has adopted the 2021 International Building, Residential, Mechanical, Plumbing, and Fire Codes, the 2021 ICC Electrical Code, 2020 NEC, and the 2021 pool/spa code, effective as of a 2024 update. The Building Department issues permits and inspects new construction in unincorporated parts of the county.

Septic: Franklin County adopted its own On-Site Sewage Disposal Systems Ordinance, effective October 1, 2025, layered on top of Missouri DHSS's statewide minimum onsite wastewater standards. The county (Building/Health Departments) administers permitting locally. I found no official county statement on composting toilets specifically, so treat that as unconfirmed and ask the county directly under the new ordinance.

Greywater: Not confirmed at the county level. Missouri's general rule (per DNR and MU Extension) is that surface discharge of wastewater effluent isn't allowed, though I found no Franklin County-specific greywater ordinance. Call the county Health or Building Department before setting up a greywater system.

Rainwater: No county restriction turned up in my research. Missouri state law protects a landowner's right to collect and use rainwater on their own property, and that appears to be the operative rule here.

Wells: Well construction follows Missouri's statewide Water Well Drillers Act rules, but Franklin County's Health Department directly inspects private wells and tests for bacterial contamination. DHSS recommends annual well water testing, and more often if the water changes character.

Utilities: I found no Franklin County ordinance that requires connecting to grid power, water, or sewer. Living disconnected appears permitted, but you're still on the hook for the county's building, septic, and well compliance regimes described above.

Bottom line: Franklin County isn't a hands-off jurisdiction. Confirm details for your specific parcel with the offices below before you commit to a plan.