ADU rules in Urbandale

Urbandale allows one ADU on a property with one or more single-family dwelling units, built with the house or added later, and expressly provides for detached ADUs separated from the house by at least six feet. Ordinance 2025-11 (8-4-2025) rewrote § 160.37 to conform to Iowa's 2025 ADU law, and Ordinance 2026-20 (5-19-2026) deleted the old listing of ADUs as a Board of Adjustment conditional use in the A-1, A-2, R-1L, R-1I and R-1S districts. The state floor, Iowa Code 364.3(23), independently requires the city to allow at least one ADU with a single-family residence.

An attached ADU, incorporated into or added onto the house and sharing at least one wall, is allowed on the same terms as a detached one, and must follow the same setback and bulk requirements as the house. Iowa Code 364.3(23)(e)(1) defines an ADU as attached to or detached from the single-family residence and requires the city to allow one.

§ 160.37(C) caps an ADU at 1,000 square feet or 50 percent of the primary dwelling unit, whichever is greater, which matches the state floor in Iowa Code 364.3(23)(a)(2). The local text does not yet carry SF 2369's 7-1-2026 measurement rules, which control: unfinished basements are excluded from the ADU's size, and the house's size means its gross living area excluding garages, decks and unheated porches. Attached ADUs follow the house's setbacks and bulk rules; detached ADUs follow the house's setbacks except that one under 14 feet tall and under 1,000 square feet needs only a 10 foot rear setback (or the house's, if less), a deliberately more permissive local rule. The code also limits a detached ADU plus other detached accessory buildings to 30 percent of the rear yard and requires 10 feet of separation from other buildings (6 feet with fire protection), see caveats.

§ 160.37 imposes no owner-occupancy requirement; the Council Letter for Ordinance 2025-11 states the city is prohibited from requiring any portion of the property to be owner-occupied. Iowa Code 364.3(23)(b)(4) bars a city from requiring the property owner to be a resident or requiring a relationship between occupants. The only owner-related rule is that a non-owner-occupied unit needs a housing inspection (rental) certificate, the same as every rental in the city.

§ 160.37 adds no parking requirement for an ADU, and the off-street parking section (§ 160.29, last amended by Ord. 2025-16 of 9-16-2025) contains no ADU-specific spaces; the lot keeps the single-family minimum of three spaces per detached house. Iowa Code 364.3(23)(b)(3) bars additional parking beyond that required for a single-family residence or a fee in lieu. § 160.37(H) requires direct access from each dwelling unit to the public right-of-way, such as a continuous sidewalk or driveway.

ADUs are allowed by right through a building permit (applied for through the city's Citizenserve permit portal). Ordinance 2026-20, passed 5-19-2026, deleted the former conditional-use listing for ADUs in the A-1, A-2, R-1L, R-1I and R-1S districts because, in staff's words, § 160.37 now 'allows Accessory Dwelling Units as permitted uses'. Iowa Code 364.3(23)(c) requires approval without discretionary review or hearing on the single-family timeline, with written reasons for any denial.

§ 160.37(E) requires any non-owner-occupied unit to meet the Urbandale Housing Code and obtain a housing inspection certificate, which is the same certificate Chapter 151 requires for every dwelling occupied by someone other than its owner (inspections at least every two years; fees set by resolution). That program is the regular rental inspection and certification program Iowa Code 364.17(3) requires of cities over 15,000, so it survives 364.3(23)(b)(2). The code contains no short-term rental rules (a search for 'short-term' returns nothing), and Iowa Code 414.1(1)(e) bars city regulation, conditional use permits, licences and fees aimed at rentals of 30 days or less. § 160.37(K) bars selling or dividing the ADU from the primary dwelling.