ADU rules in Davenport

Davenport lists Dwelling - Accessory Dwelling Unit as a permitted use in R-1, R-2, R-3 and R-4 (Table 17.08-1), limited to one per lot, in the rear yard, meeting detached-garage setbacks (4 feet from interior side and rear lot lines under §17.09.030). Iowa Code 364.3(23), as amended by SF 2369 effective 7-1-2026, requires a city to allow at least one ADU on any lot with a single-family residence in a district where a single-family residence is an allowed principal use, so the floor also reaches R-MF, C-T, C-1, C-2 and C-V lots, where the table permits single-family homes but leaves the ADU row blank. A detached ADU can be a converted detached garage.

Davenport's code contradicts itself here: the §17.08.050 definition says an ADU "may be within or attached to the principal dwelling unit structure or within a detached accessory structure", but §17.08.030(M)(2) says "Accessory dwelling units must be located within a detached structure." Iowa Code 364.3(23)(e)(1) defines an ADU as one "either attached to or detached from" the house, and (d) voids conflicting local text, so an attached or internal ADU (basement, addition, conversion) must be allowed. The detached-only sentence is not enforceable against an application that meets the statute.

Davenport's §17.08.030(M)(6) says "No accessory dwelling unit may exceed 1,000 square feet in gross floor area", and a detached ADU takes the 20-foot detached-garage height under (M)(5). State law sets the cap at the larger of 1,000 square feet or 50 percent of the house, measured on gross living area excluding garages, decks and unheated porches, with unfinished basements left out of the ADU's size (SF 2369, effective 7-1-2026). So a house with more than 2,000 square feet of living area may have a larger ADU than the city text allows. Height, setback and coverage limits may not be stricter than those for the house itself.

Davenport's code still says "One of the dwelling units must be occupied by the owner of the property" (§17.08.030(M)(1)), unchanged since adoption and not amended through the 7-22-2026 codification or any council agenda through 10-14-2026. Iowa Code 364.3(23)(b)(4) bars a city from "requiring the property owner to be a resident", and (d) makes conflicting local text void, so no owner occupancy can be required at application or afterward.

Davenport's §17.08.030(M)(8) states that no additional parking is required for an ADU and that the principal structure's required parking must be maintained. When a detached garage is converted, the ground floor may become the ADU only if the minimum off-street spaces for the house remain on site (M)(7). This matches Iowa Code 364.3(23)(b)(3), which bars parking beyond the single-family requirement or a fee in lieu.

Table 17.08-1 marks the ADU "P" (permitted by right) in R-1 through R-4, so it needs a zoning and building permit with no special use hearing. Iowa Code 364.3(23)(c) requires approval "without discretionary review or hearing" on the single-family timeline, with any denial in writing stating the remedy. In districts where the table is blank for ADUs but permits single-family homes (R-MF, C-T, C-1, C-2, C-V), the state floor still requires ministerial approval.

Every rented dwelling unit, an ADU included, needs a certificate of structure compliance, an annual rental license, landlord education within six months of a first license, and a 24-hour emergency contact who can reach the site within eight hours (§8.15.145(A)); rentals start on a two-year inspection cycle (new buildings get four years). Davenport's code has no short-term rental chapter (an eCode360 search for "short-term rental" and "short-term rentals" returns no hits), and Iowa Code 414.1(1)(e) bars STR-specific regulation and STR license or permit fees, so a nightly or weekly rental of an ADU is regulated only like any other residential rental. The city's college/university-zone occupancy rules in §8.15.180 can limit occupants of single-family rentals near campuses.