What are the tiny house laws in Missouri?

You can live in a tiny house in parts of Missouri, but there is no confirmed statewide permission covering every parcel^1,2. We could not confirm a statewide tiny-home occupancy standard. Ask your county planning office about the home you want. Inside city limits, ask the city planning office.

Describe your home precisely: a foundation house, a movable unit or an additional dwelling beside an existing house. Ask how the local office will classify it. Missouri adopts building codes locally, so ask the jurisdiction covering your site for a construction answer². Ask about septic separately: most installations and repairs need their own construction permit³.

Missouri’s county-zoning statute for qualifying first-class charter counties sets no statewide minimum house size⁴. The statute lets qualifying first-class charter counties regulate building size in unincorporated areas⁴. It alone cannot tell you the minimum floor area for your lot⁴.

Ask your local planning office for the dwelling-size rule in your zoning district. Ask the building office which adopted code and amendments apply to your design. Missouri leaves code adoption to local jurisdictions². Bring a floor plan that shows how much living area you propose. Get a written answer about your actual design before you order the home or commit to buying land.

Most Missouri septic installations and repairs need a construction permit before you start work³. Some single-family residential lots qualify for an exemption, but your septic authority must confirm it³. Under state guidance, a residential lot smaller than 3 acres needs a permit, and some counties do not offer the acreage exemption³.

Use the DHSS Onsite Wastewater Treatment Program's county selector to find the authority for your address³. State septic application fees are temporarily suspended effective August 28, 2026³. Ask that authority about current charges and the exemption before you arrange excavation. A qualifying local government or district can require you to connect where an available sewer system serves its territory⁵.

Call the planning and building offices serving your exact parcel first, because Missouri adopts building codes locally². Send the address, floor plan and a description of your home. Ask whether you can live there permanently. Ask which code applies and whether the district sets a minimum dwelling size.

For a new manufactured home or modular unit, ask the Missouri Public Service Commission's Manufactured Housing and Modular Units Program about construction and setup issues⁶. The program enforces building codes, safety standards and setup requirements for those new homes and units⁶. Confirm your wastewater plan separately with the septic authority before you start work³. Get written answers tied to your parcel and proposed home before you pay a nonrefundable deposit.