Leon County, FL Accessory Structures: ADU Rules (2026)

In November 2023, the Leon County Board of County Commissioners adopted Ordinance No. 23-12, amending Land Development Code Sec. 10-6.803 (Accessory uses) and Sec. 10-1.101 (Definitions) to expand accessory dwelling units, consistent with Florida's push to increase housing supply. Under the amended Sec. 10-6.803(b), ADUs 'may be allowed in all zoning districts' provided the standards are met. Key rules for an ADU accessory to a single-family home in unincorporated Leon County: no more than one ADU per lot, and the ADU is exempt from residential density calculations; the ADU must comply with the zoning district's setbacks and height limits; a detached ADU may not exceed 800 square feet of heated/cooled (air-conditioned, enclosed) floor area, nor more than 5% of the total lot area; an attached ADU may not exceed 45% of the principal home's enclosed floor area, nor 800 sq ft. Detached ADUs must be located in the side or rear yard (rear yard required if the lot is served by an alley); front-yard or side-corner placement is allowed only when the principal structure is set back at least 50 feet and the ADU is set back at least 30 feet from front and side-corner lines. A mobile home, manufactured home, or storage shed may not be used as an ADU, and the ADU must be permitted as a habitable structure. Larger setbacks apply in the Residential Preservation district (105% of the side and 110% of the rear principal-structure setback). Florida law also limits how the county may regulate ADUs.