ADU rules in St. Louis County, MO — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
St. Louis County's Zoning Ordinance §1003.020 defines 'family' as related individuals or a group of no more than 3 unrelated persons. Two kitchens maximum per dwelling unit, which effectively prohibits unpermitted ADUs in standard single-family zoning.
Unlike California or Oregon, Missouri has no state ADU pre-emption law. St. Louis County's §1003.020.59 defines home occupation narrowly, and §1003.020 (family definition) limits 'two kitchens' per single-family unit. Adding a separate dwelling typically requires conditional use approval or a duplex zoning change. Re-occupancy permits (§1110.1045) are required when any new tenant moves in.
Stop-work order; civil penalties; ordered removal of unauthorized second kitchen; re-occupancy permit denial.
Other ordinances people look up for this city. Green dot = verified primary-source excerpt.
St. Louis County, MO
New trees may not be planted on a St. Louis County right-of-way between the sidewalk and the curb (SLCRO §1218.140). Existing right-of-way trees are owned by...
St. Louis County, MO
SLCRO §607.1005 permits residential backyard composting countywide if located ≥3 ft behind the main residential structure, screened from neighbors near prope...
St. Louis County, MO
Grass and weeds on residential property in unincorporated St. Louis County cannot exceed 8 inches in height. Property owners have 7 days after a violation no...
St. Louis County, MO
Under Missouri Constitution Article XIV §2, registered patients and adults 21+ may cultivate up to 6 flowering and 6 non-flowering marijuana plants per regis...
St. Louis County, MO
Missouri Amendment 3 (2022) legalized adult-use cannabis. St. Louis County allows licensed dispensaries in commercial zones subject to local zoning review. M...
St. Louis County, MO
SLCRO §1005.095 recognizes subdivision trust indentures — private agreements between trustees and homeowners — as the primary tool for enforcing subdivision-...
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