Fort Smith, AR Accessory Structures: ADU Rules (2026)

Arkansas grants planning and zoning authority to cities of the first class through A.C.A. §14-56-401 et seq. (Local Planning Act). Section 14-56-416 authorizes adoption of zoning ordinances regulating the use of buildings, density of population, and area of lots. Fort Smith's Unified Development Ordinance, adopted in 2011, consolidates zoning, subdivision, and related development standards into a single instrument. The UDO divides the city into residential districts (typically R-1 single-family, R-2 two-family, R-3 multi-family, and related categories) along with commercial, industrial, and mixed-use districts. Whether an ADU is permitted in a given district, whether it must be attached or may be detached, minimum and maximum unit size, off-street parking requirements, owner-occupancy obligations, and rental restrictions are all set by the UDO. The Fort Smith Planning Commission, established under A.C.A. §14-56-404, hears special use permit applications and recommends UDO amendments to the Board of Directors. The Board of Zoning Adjustment hears variances under A.C.A. §14-56-416(b)(2)(C)(ii). Because Arkansas has not enacted ADU preemption, there is no statutory ministerial-approval requirement, no state-mandated unit size minimum, and no statewide ban on owner-occupancy or rental restrictions. Property owners should consult the UDO and the Fort Smith Department of Development Services for a written zoning determination before designing an ADU. Building construction must additionally comply with the Arkansas Fire Prevention Code (adopted statewide IFC) and any locally adopted building codes — Fort Smith typically operates under the International Residential Code.