ADU rules in Key West

The SF (single-family residential) district accommodates one accessory attached or detached unit per principal dwelling unit, but only if the unit wins a building permit allocation under the BPAS growth cap and meets the affordability and occupancy criteria of Sec. 122-233. No other residential district (LDR-C, MDR, MDR-1, MDR-C, HDR, HDR-1) lists accessory units; a separate accessory unit infill program covers mixed use and commercial districts.

Same authorization as detached: one accessory attached or detached unit per principal dwelling in the SF district, subject to BPAS allocation and the Sec. 122-233 criteria. Under the BPAS definitions, an accessory unit cannot take up more than 40 percent of the principal structure.

The size band appears identically in Sec. 122-233(a)(10), the Sec. 86-9 definition, and the Sec. 108-986 BPAS definition. Accessory units are exempt from lot coverage, impervious surface (if stormwater is contained on site as certified by a licensed engineer), and landscaping requirements, and must keep a minimum 5-foot rear and side setback.

The zoning sections (122-232 to 122-234) impose no ongoing owner-occupancy rule, but the BPAS definition requires that when an accessory unit occupancy permit is originally initiated, the principal unit must be owned and occupied by a permanent resident. The accessory unit itself must be occupied by permanent residents as a primary residence.

Sec. 122-233(a)(8): 'There shall be no additional parking requirement for the Accessory unit.' In the separate mixed-use accessory unit infill program, applicants may provide two bicycle or scooter parking spaces per unit as an alternative to seeking parking variances.

Accessory residential units are listed among the permitted uses of the SF district (Sec. 122-235(1)), so no conditional use approval is needed. However, every unit must first win a building permit allocation under the BPAS growth cap (counted as 0.78 dwelling unit), and a second bedroom requires a planning board variance. BPAS applications for accessory units can be received at any time during the allocation year.

The rent cap and perpetual recording are in Sec. 122-233(a)(1) and (b); the no-transient-rental and no-condo-sale rules are in the Sec. 86-9 accessory unit definition and Sec. 122-233(a)(3).