Unincorporated Maries County, Missouri does not require a county building permit to build a home1. Maries County has no confirmed countywide zoning ordinance, but that does not mean every use is unrestricted2. Missouri's Department of Health and Senior Services handles onsite wastewater construction permits in Maries County3.
At a glance
- Building permit
- Not required in unincorporated Maries County1
- Zoning
- No zoning office; no confirmed countywide ordinance2
- Septic permit
- DHSS handles permits; approval or a confirmed exemption is needed before work begins3
- RV / tiny home living
- No published county rule found either way; ask the Commission2
- Owner-builder exemption
- Not confirmed; there is no county permit process to be exempt from4
- Minimum lot size / setbacks
- Not published; no zoning ordinance was found2
Who to call
Also useful
General county government; the office to ask about county roads, floodplain status, or zoning/subdivision questions, since Maries County has no building, planning or zoning department
Property records
Maries County Assessor's Office
Property assessment, parcel records and valuation for Maries County
211 4th Street, Courthouse, P.O. Box 188, Vienna, MO 65582
Health department
Missouri Onsite Wastewater Treatment Program (DHSS)
Onsite wastewater treatment system (septic) construction permits for Maries County, since the Phelps/Maries County Health Department stopped issuing them locally on October 16, 2024
PO Box 570, Jefferson City, MO 65102-0570
Contact details are copied from each office’s official page and were checked against it on September 29, 2026.
Do you need a building permit in Maries County, Missouri?
No county building permit is required to build or renovate a home in unincorporated Maries County: the county's own website lists no building, code-enforcement or inspection office among its departments1. Missouri law lets only counties of the first or second classification adopt a residential building code, and nothing on Maries County's site indicates it has done so5. Because there's no county permit process, there's also no confirmed county inspection, certificate-of-occupancy or owner-builder-exemption rule — those questions simply have no official Maries County answer yet4. If you hire a contractor, that relationship and any warranty are between you and them, not enforced through a county permit.
Who do you call about land-use and building questions in Maries County?
Maries County has no building, planning or zoning department, so there's no dedicated land-use office to call12. The Maries County Commission, at 573-422-3388 or [email protected], is the general county government office and the practical place to start with a road, floodplain or land-use question6. The Maries County Assessor's Office, at 573-422-3540, keeps parcel records, acreage and property-tax valuation and is worth calling to confirm the boundaries and classification of a specific tract7. For septic work, call Missouri's Onsite Wastewater Treatment Program at 573-751-6095; DHSS is the permitting authority listed for Maries County83.
Does Maries County have zoning?
Maries County's own website lists no planning or zoning department, and no official record shows the county has ever put a zoning question to voters2. Missouri law lets a county like Maries adopt zoning only after voters approve it in a countywide referendum, and nothing found on the county's site shows that vote has happened9. That means there is no confirmed countywide rule on lot size, setbacks, building height, accessory dwellings, or RV and tiny-home occupancy — not that these are guaranteed unrestricted, just that no ordinance addressing them has been found, so call the County Commission before you assume anything6. Zoning in Missouri generally applies only inside incorporated cities, so if your parcel sits inside Vienna's city limits rather than unincorporated Maries County, the City of Vienna's rules would apply instead2.
How do septic (onsite wastewater) permits work in Maries County?
The Missouri Department of Health and Senior Services is the onsite wastewater permitting authority for Maries County3. A construction permit is required before installing or repairing most systems, although some single-family residential lots may qualify for an exemption; do not start work until DHSS issues the permit or confirms the exemption3. Apply through Missouri's Onsite Wastewater Treatment Program at PO Box 570, Jefferson City, MO 65102-0570, phone 573-751-60958. Only 0.7% of Maries County land has soil without severe limitations for a conventional drain field, so get the site evaluated before fixing a house location or purchase budget10. Application fees for onsite sewage system construction, modification and repair are temporarily suspended as of August 28, 2026; ask DHSS whether that suspension remains in effect when you apply3.
Can you live in an RV or tiny home on your land in Maries County?
We could not confirm a Maries County rule addressing RV or tiny-home occupancy on private land, and the county has no zoning or planning office2. Call the County Commission at 573-422-3388 before setting up a long-term RV, park model or tiny home, especially if the parcel may be inside Vienna's city limits, where separate rules could apply6. For an unsewered homesite, DHSS still requires a construction permit for most onsite wastewater systems unless it confirms that the lot qualifies for an exemption3.
Building a home in Maries County: the steps, in order
- Confirm whether the parcel is inside Vienna's city limits or in unincorporated Maries County, because the county zoning answer does not establish the rules inside an incorporated city2.
- Call the Maries County Assessor's Office at 573-422-3540 to confirm the parcel's recorded acreage and existing structures7.
- Contact Missouri's Onsite Wastewater Treatment Program at 573-751-6095 before fixing the house location; DHSS must issue the septic construction permit or confirm that the lot is exempt before work begins83.
- Because unincorporated Maries County does not require a county residential building permit, arrange your own construction supervision and quality checks1.
- Ask the Maries County Commission about county-road access, culverts and the parcel's floodplain status before moving equipment onto the site6.
- If the entrance meets a state highway, obtain the required MoDOT right-of-way permit before constructing or modifying the driveway11.
What to check before you buy land in Maries County
Test the soil before you commit: only 0.7% of Maries County's land has soil without severe limitations for a conventional septic drain field, so budget cautiously and get a site evaluation early10. About 70.2% of the land has a slope of 15% or less, and 54% is wooded, so compare the cost of clearing and grading each candidate homesite1213. Maries County has about 16 people per square mile, and the nearest city of 100,000 or more is roughly 63 miles from the county's center1415. Farmland value averages about $3,134 per acre, while the typical home value is about $260,1601617. Maries County's effective property-tax rate is about 0.6%, with a median annual bill near $1,0881819. A septic inspection is not automatically required for every Missouri real-estate transaction, but a buyer or lender may request one and it must be performed by a licensed individual20. Before closing, ask the County Commission whether the parcel is unincorporated, lies in a mapped flood hazard area, or is subject to a subdivision rule69.
Watch-outs
- Farm buildings and structures used strictly for agriculture (not a residence) get a separate state-law exemption from local building and land-use restrictions outside mapped flood-hazard areas, if Maries County ever regulates them21.
- Whether unincorporated Maries County has ever adopted subdivision regulations under state law is unconfirmed; ask the County Commission before platting a new parcel69.
- No floodplain administrator is published on the county's site; ask the County Commission whether your parcel is in a mapped flood hazard area before you build622.
Sources
- Maries County, Missouri - Official County Website (department directory) (2026 county census)
- Maries County, Missouri - Official County Website (department directory) (2026 county census)
- OWTS Construction Permit Process, quoted and re-checked
- (2026 county census)
- RSMo § 64.170 — County commissions control construction and issue building permits (Missouri statewide rule), quoted and re-checked
- Maries County Commission (mariescountymo.gov)
- Maries County Assessor's Office (mariescountymo.gov)
- Missouri Onsite Wastewater Treatment Program (DHSS) (health.mo.gov)
- RSMo § 64.090 — Planning and zoning powers of county commission (Missouri statewide rule), quoted and re-checked
- Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
- Permits | Missouri Department of Transportation (Missouri statewide rule), quoted and re-checked
- Share of land at 15% slope or less: Bolthole Index county data
- Wooded share of land: Bolthole Index county data
- Population density: Bolthole Index county data
- Distance to the nearest metro area: Bolthole Index county data
- Farmland value per acre (USDA census): Bolthole Index county data
- Typical home value (Zillow): Bolthole Index county data
- Effective property tax rate: Bolthole Index county data
- Median property tax bill: Bolthole Index county data
- Frequently Asked Questions, quoted and re-checked
- Building and land use restrictions — exemptions — limitations on use of powers, quoted and re-checked
- Laws and Regulations That Might Affect You if You Mine Sand or Gravel From Missouri Streams (Missouri statewide rule), quoted and re-checked
Written September 29, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.