Accessory Structures in Missouri (2026)

The St. Louis County Zoning Ordinance controls second dwellings through its definition of family in §1003.020. A family…

Cass County allows a small accessory dwelling, what the Zoning Order calls a 'transitional living dwelling,' only by…

Kirkwood allows one accessory dwelling unit per single-family lot, capped at 750 square feet and two bedrooms, on a lot…

O'Fallon allows a secondary "carriage house" dwelling only inside the Mixed-Use Traditional Development District…

Missouri has no statewide ADU mandate; ADU regulation is delegated to counties under Mo. Rev. Stat. Ch. 64. The Boone…

Columbia, Missouri allows one accessory dwelling unit per single-family lot in the R-2 and R-MF districts by right, and…

Unincorporated Greene County zoning lets homeowners add a garage apartment, guest house, or servant's quarters as an…

In Independence's Historic Downtown Square District, one accessory dwelling unit per lot is allowed inside the main…

Unincorporated Jackson County allows an accessory dwelling unit only in the AG and RR zoning districts, and only with a…

Jefferson County allows a permanent accessory dwelling unit, such as a mother-in-law cottage, in residential zoning…

Kansas City allows one accessory dwelling unit per lot with a detached house, capped at 800 square feet with a…

Lee's Summit caps a backyard accessory dwelling unit at 1,000 square feet or 50 percent of the main house's floor area…

St. Louis allows one attached or detached accessory dwelling unit per residential parcel, capped at 25 feet in height…

Lee's Summit's park impact fee, charged citywide on new building permits since July 1, 2025, does not apply to…

Within Independence's West Central Overlay District, the lot owner must live in either the main house or the ADU, never…

Kansas City requires the property owner to live in either the main house or the accessory dwelling unit, backed by a…

Kirkwood requires the property owner to actually live on site whenever an accessory dwelling unit is occupied. Under…

Building an accessory dwelling unit in Lee's Summit means attesting to owner occupancy on the building permit…

An accessory dwelling unit in Lee's Summit cannot be rented out as a short-term rental, period. The UDO's ADU occupancy…

Cass County allows a small accessory 'transitional' dwelling for family members needing care, but the Zoning Order…

ADUs in Independence's West Central Overlay District can't be rented for under 30 days unless approved as a bed and…

Columbia, Missouri allows an ADU to operate as a short-term rental only if just one dwelling on the property is…

Kansas City caps short-term rentals at one per parcel: if your lot has just one principal dwelling unit, you can rent…

Boone County zoning bars building a shed or other accessory structure before the main house is under construction, and…

In unincorporated Cass County, a one-story detached shed, tool building or similar accessory structure under 400 square…

A carport in unincorporated Clay County requires a building permit from the Building Division and must meet zoning…

In Columbia, Missouri, detached carports and other accessory structures on one- and two-family lots must sit behind the…

Florissant caps backyard sheds and other accessory buildings at eighteen feet and bars them from exceeding the height…

In unincorporated Greene County, sheds and other accessory buildings are capped by lot size, from 500 square feet on…

Independence requires a 5-foot interior setback for detached accessory buildings and sheds in most residential…

In unincorporated Jackson County, a detached carport must sit in the rear yard and meet the principal building's side…

Jefferson County caps combined accessory-building square footage by district under UDO Section 400.2870: up to 4,000…

Kansas City treats carports as accessory structures: they can't sit in the front or street-side yard, need at least 1.5…

Kirkwood caps detached accessory structures like sheds at 24 feet or 1 1/2 stories, limits total accessory coverage to…

A storage shed in a Lee's Summit residential district must sit at least 3 feet from the side and rear property lines…

O'Fallon caps a residential utility shed at 200 square feet and 15 feet in height, keeps it out of the front and side…

Springfield residential accessory structures like sheds must sit at least three feet from rear and side lot lines, stay…

St. Charles County caps total accessory-structure square footage by lot size, starting at 1,200 square feet on parcels…

St. Louis exempts small detached sheds from a building permit only if they are 120 square feet or less, under 12 feet…

A detached, one-story storage shed, tool shed, or playhouse in unincorporated St. Louis County needs no building permit…

Boone County zoning bans converting a garage or other accessory building into living space, with the only exception…

Converting a garage into living space in unincorporated Clay County requires a building permit and must meet…

Kirkwood lets homeowners convert a detached garage into an accessory dwelling unit under Zoning Code § 25-45(b), but…

Converting a garage into living space for an accessory dwelling unit is allowed in Lee's Summit, but only if the…

Missouri requires factory-built manufactured tiny homes to meet federal HUD standards under state law, with…

Independence has no standalone tiny-home zoning; a tiny house is only legal as a West Central Overlay District ADU…

Kansas City adopted the International Residential Code's Appendix Q for tiny houses in 2020, applying that model code…

Springfield, Missouri caps tiny home communities at 11 dwelling units per acre and confines them to planned development…