In a perfect world, people who wanted to reduce their environmental impact by downsizing to a tiny home would just be able to do that. But tiny homes aren’t just small houses. In addition to often having to meet residential building codes, they frequently have a whole set of specific laws they need to abide by.
Regulations around tiny houses in the United States are complex and changing, and it’s important to stay on top of them if you want the law on your side. This month, we’re digging deep to present you with a complete guide to Missouri tiny house laws.
Before we start, please understand that we at Green Home Gnome are not lawyers. The Gnome is not a lawyer. He is a gnome. Great at parties—not at all good at legal advice. Ask me how I know. Nothing that follows should be considered legal advice. Please do your own due diligence before trying to live the tiny house lifestyle in Missouri and consult a legal professional if you’re unclear about any local regulations.
A Complete Guide to Missouri Tiny House Laws
Missouri is a difficult state for tiny home owners and prospective owners because there are no statewide tiny home building laws. Instead, there are layers on layers of codes and regulations that will impact what kind of home you can live in and where you can live in it. We’ll start at the broadest level and then get more specific about local laws as we go.
International Building Codes
With no statewide building legislation on the books, many counties and municipalities rely on international building codes to determine if a home meets legal building standards. Missouri has adopted the International Residential Code, the International Building Code and the International Code Council’s (ICC) codes on the following: fire, plumbing, mechanical, property maintenance, energy conservation, existing buildings, fuel gas, private sewage disposal, performance, swimming pools and spas.
That said, codes are locally adopted and enforced, and any local jurisdiction can change anything they’d like about them, so local regulations may or may not be anything like what the ICC envisioned.
If you’re building a tiny home in a place where international codes are in effect, you’ll need to pay particular attention to the International Residential Code to ensure that your home will be legal.
International Residential Code
Appendix Q of the International Residential Code (IRC) deals with tiny houses and outlines the different rules and additional building regulations that apply to them.
It notes that the provisions contained therein aren’t mandatory unless specifically referenced by whichever governing body adopts them. That means that local jurisdictions may or may not put them into effect and may or may not put them into effect as they’re written in the IRC.
The IRC specifies that tiny homes are homes 400 sq. ft. or less, excluding lofts. To meet IRC Code, tiny houses need to be built with these specifications in mind:
- Ceiling height needs to be at least 6 feet 8 inches in any living area. Bathrooms and kitchens can be 6 feet 4 inches in height. Headroom in stairways up to a loft can be 6 feet 2 inches.
- Lofts must have a minimum floor area of 35 sq. ft.
- Stairs up to a loft need to be at least 20 inches wide below the handrail and at least 17 inches at or above it.
- Egress roof access windows in a loft can contribute to requirements for emergency escape as long as the bottom of the window opening is 44 inches or less above the loft floor.
These are just some major highlights. For complete information, consult the Appendix and the Code itself.
There are no federal laws to take account of when it comes to tiny houses. The National Electrical Code is in effect in Missouri, but it’s not a law and every local government has the power to adopt, not adopt or amend that Code as they deem necessary.
Missouri State Transportation Laws
In Missouri, as in any U.S. state, you’ll be bound by strict regulations about house size if you opt to put a tiny home on wheels. Tiny houses on trailers are categorized as “travel trailers” in Missouri, much like recreational vehicles. The state defines a travel trailer as:
“a vehicle, mounted on wheels, designed to provide temporary living quarters for recreational, camping or travel use, of such size or weight as to not require a special highway movement permit when towed by a motorized vehicle, and of gross trailer area not to exceed three hundred twenty square feet (29.7m2).”
To get around state and interstate highways without a permit, then, Missouri law says a travel trailer must be less than 14 feet high. It must be less than 13 ½ feet high on smaller highways, so better to be safe and go with that number. Travel trailers can be a maximum of 8 feet, 6 inches wide (excepting clearance lights and rearview mirrors) and 45 feet long.
Missouri State Laws and Zoning
As the Tiny House Society explains, you can’t live in a travel trailer in a city, nor can you park one on a street or in any public area in Missouri. If there’s a public disaster, however, it’s ok to use them as emergency shelters.
Aside from that, Missouri doesn’t have any state-wide regulations pertaining specifically to where you can build or put tiny homes. In many places, tiny homes on trailers are relegated to zones designated for RV or mobile home parks, but that’s up to a local municipality to determine. And in many places, there are requirements that a home in a residential zone needs to have a minimum square footage of floor area, but again, that’s up to local officials.
So, to figure out if you can legally live in a tiny house in the place you want to, you need to look at regional and municipal bylaws.
County Laws Pertaining to Tiny Houses
Not all counties have laws on the books about the construction or placement of tiny homes. Making the situation more complex, counties may or may not be the final say when it comes to tiny house regulations.
The county might specify that tiny home owners need to reach out to local municipalities or city officials, fire protection districts, subdivision trustees and sewer districts before starting work on a tiny house.
Some counties do offer guidance around building regulations and tiny house laws, however. These include the following counties:
Franklin County will permit detached accessory dwelling units (ADUs)that are not mobile homes, although it does allow mobile homes as dwellings for people with approved medical exceptions. You can check to see if you need a conditional use permit. Lots must be a minimum of 1 acre in order to have an ADU.
Union will allow ADUs in their zoning code for people experiencing medical hardship. In both city and county, ADUs must be a maximum of 500 sq. ft. or 50% of the size of primary residential structures, whichever is less. They must be connected to public water and sewer service if it’s available. If not, hookups need to comply with County and State laws.
Jefferson County will allow a permanent accessory dwelling unit on residential properties, as long as the unit isn’t a mobile home or a shipping container. If available, the unit has to be connected to public water and sewer service. Otherwise, hookups must comply with County and State regulations. There’s more information about setbacks and other requirements here.
There are no zoning restrictions, building codes or regulations in this county. You won’t need a building permit in the unincorporated sections of the county. The only thing you’ll need any kind of permit for is a septic tank system. Have fun, everybody!
St. Louis County
In 2020, St. Louis County published this Residential Tiny Houses Checklist. It serves as a guide to the policies and codes that apply to tiny homes. The checklist specifies that both factory-built tiny homes and tiny houses constructed on-site within unincorporated residential areas must be on a permanent foundation.
Licensed contractors must complete and inspect work related to electrical, plumbing and mechanical systems. Architectural drawings must be submitted with a permit application for a site-built tiny home. Prefab tiny homes must be “approved, stamped and numbered by the Missouri Public Service Commission (Mo-PSC).”
Tiny houses on wheels are not permitted as permanent residences within residential neighborhoods in Unincorporated St. Louis County, but they are allowed in a designated mobile home park.
Minimum room dimensions are based on the number of occupants. Information about ceiling heights, passageway widths and clearances, as well as other code requirements, can be found in the checklist.
In April of 2022, Adam Rollins of the Warren County Record reported that the planning and zoning board was discussing the possibility of permitting tiny home developments in the County. A preliminary draft of the possible new rules around these developments suggests that tiny home communities could be confined to areas specifically zoned for them.
Washington County relies on its city and town halls to issue building codes and zoning laws. In Potosi, single-family residential buildings must be a minimum of 700 square feet. Irondale follows the International Building Code, which suggests it would be open to tiny homes as outlined in Appendix Q of the IRC. In rural areas, building codes on private properties seem less applicable.
Municipal Laws and Information Pertaining to Tiny Homes
Not all municipalities in Missouri have laws on the books regarding tiny homes. Those that do include:
Branson specifies that Appendix Q of the IRC is part of its building code, suggesting that it’s a little friendlier to the idea of smaller homes. The city is also home to the Elevate Community, a tiny home village for low-income folks that started with 48 homes and is growing through donations.
In Columbia, tiny homes can’t be primary residences because, according to their zoning regulations, residential homes must have a minimum square footage of 650 sq. ft.
Columbia will allow an accessory dwelling unit for an existing single-family house in zones R-2 or higher, however. Any secondary residential dwelling unit must be smaller than 75% of the total square footage of the primary dwelling or 800 sq. ft. Whichever is smaller.
Jefferson City’s Activate Jefferson City 2040 plan includes the goal of diversifying its housing, in part through tiny homes and ADUs. In a community engagement survey, participants advocated for tiny homes, suggesting that there’s an interest in the city.
It’s illegal to park a travel trailer on a street or a public space within the city limits. Kansas City seems to be warming to tiny homes, however. It has adopted Appendix Q of the IRC. And in 2021, it announced that it would be building a tiny home village of 140 beds to provide transitional housing for its unhoused residents. This follows a tiny home community for veterans that was built by the Veterans Community Project.
In 2021, Lake Ozark approved a Planning and Zoning Commission recommendation for a zoning change that allowed for a tiny house community of 8 homes under 400 sq. ft., built by LCMC Enterprises. It was hoped the community would give the local workforce access to affordable housing.
The decision could open the way for other tiny houses or tiny house communities. In case you’d like to get plans together in the lake area, the Lake Ozark Fire Protection District, which issues building permits, uses the International Building Code and National Fire Protection Association (NFPA) codes.
Saint Charles has a minimum 1,000 square-feet floor area requirement for single-family homes in residential areas on its books.
The City of St. Louis built their first community of tiny homes in 2020 on the site of a former RV park. The community of 50 homes was a project to mitigate the effects of COVID-19 on people experiencing homelessness.
While St. Louis has adopted the IRC, it hasn’t adopted Appendix Q. It has its own ordinances around tiny homes, which specifies that they must be “anchored to an approved foundation” to be considered a dwelling unit.
Tiny houses on a permanent chassis with wheels and Housing and Urban Development (HUD) or Federal Housing Administration (FHA) certification can be placed in a mobile home park. Any other type of tiny house on wheels is considered a travel trailer and can only be used for recreation.
Tiny houses on foundations must connect to public utilities. Read the ordinances for more detailed information.
Springfield is home to Eden Village, a tiny home community for people who are disabled and experiencing homelessness. That project was so successful that an Eden Village 2 was completed in 2021.
The city’s zoning regulations permit tiny home communities in “planned development districts and manufactured home community districts.” They also permit tiny houses on permanent foundations. Appendix Q is adopted into the Code—check out the regulations for specific requirements for footings.
There are a lot of great reasons why people dream about the freedom of downsizing to a tiny home. If you don’t live in the right place to build your own tiny house and become a tiny house owner, however, don’t give up. The most tiny-house friendly places in the States didn’t get that way through luck. They got there through advocacy.
If you don’t like the rules you see in your part of Missouri, the American Tiny House Association offers this ten-step guide to initiating tiny house friendly zoning changes. It might get you started on the road to making your town or county more open to the tiny house movement. Good luck.