Surprise, AZ Accessory Structures: ADU Rules (2026)

18, lets a single-family lot host one attached ADU plus one detached ADU if the lot is under an acre, the same combination if the lot is an acre or more, or one attached plus two detached units on a lot of an acre or more when at least one of the extra units is a restricted-affordable dwelling unit. Every ADU is capped at the lesser of 75 percent of the existing single-family home's gross floor area or 1,000 square feet. 4 grants specific relief from standard zoning rules: an ADU only needs a 5-foot rear setback and a 5-foot side setback rather than the district's normal setbacks, it follows the same front setback and building frontage rules as the primary home, and the city cannot require any additional parking space or in-lieu parking fee to accommodate it.

Eligible lots cannot sit on tribal land or within the territory near a military airport, general aviation airport, or FAA-licensed public airport. 5 makes most ADU applications ministerial: the community development director designates a staff reviewer who must determine administrative completeness within 30 days, and a resubmittal after an incompleteness notice gets a 15-day review turnaround. No public hearing, variance, conditional use permit, or special exception is required for a qualifying ADU; the applicant only needs a building permit. If an application is denied, the applicant can appeal to the board of adjustment or, under Section 102-2, challenge only whether the article's objective criteria were met.