Iowa City, IA Accessory Structures: ADU Rules (2026)

Iowa Code Chapter 414 (Municipal Zoning) grants Iowa cities authority to regulate the use of buildings, structures, and land. Section 414.1 empowers cities to divide territory into districts; §414.2 lists permissible regulatory purposes; §414.3 requires zoning to be in accordance with a comprehensive plan; §414.7 establishes the board of adjustment with variance and special exception authority. Iowa City's Zoning Code at Title 14 divides the city into residential, commercial, industrial, and overlay districts. Section 14-4B-4A specifically addresses accessory apartments, generally permitting them as accessory uses in certain single-family districts subject to dimensional standards (commonly a unit-size cap expressed as a percentage of the principal dwelling, an owner-occupancy requirement, off-street parking, and limits on the number of bedrooms). Whether an accessory apartment is permitted by right, by special exception, or requires a provisional use approval depends on the underlying base district under Title 14. The Iowa City Board of Adjustment, established under Iowa Code §414.7, hears variance and special exception applications under §414.12. Because Iowa has no statewide ADU preemption, there is no ministerial-approval mandate, no state-mandated minimum size, and no statewide bar on owner-occupancy or rental restrictions. Construction must additionally comply with the Iowa State Building Code under Iowa Code Chapter 103A. Applicants should request a written zoning determination from Neighborhood and Development Services before design.