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

Land Development Code § 2.21.05.6 treats a guest house or garage apartment as a permitted accessory use in any zoning district, not just the county's residential categories, once it sits on a lot with an existing principal dwelling. The section imposes three specific limits. First, "no more than one guest house shall be permitted on any lot or parcel," so a property owner cannot add a second garage apartment or guest cottage once one already exists. Second, the accessory unit has to be detached: it "may be connected by a covered walkway" to the main house, but it cannot share a common wall or be built as a true addition, which is what distinguishes a garage apartment from an ordinary in-law suite attached to the primary structure. Third, size is capped relative to the main house rather than to a flat number: "the guest house shall not exceed the total square footage of the principal structure located on the lot," so a 1,800-square-foot home caps its garage apartment at 1,800 square feet, and a smaller home caps it correspondingly lower.

Because § 2.21.05 governs accessory uses generally, a garage apartment also has to clear the same setback and hazard rules that apply to any accessory structure in the same section, including staying out of intersection sight triangles and meeting the five-foot side/rear setback, or the district's front setback if placed in a front yard, unless the specific accessory-use rule for that structure type says otherwise.