Accessory Structures in Surprise, AZ: What Residents Actually Need to Know

If you live in Surprise or are thinking about moving there, accessory structures are one of those things you probably won't think about until they affect you directly. Surprise has 2 specific rules on the books covering different aspects of accessory structures, and some of them might surprise you.

ADU Rules

Surprise allows one attached and one detached accessory dwelling unit on most single-family lots under Article XI, capping each ADU at 1,000 square feet or 75 percent of the primary home's floor area, whichever is smaller, and letting most applications skip a public hearing entirely.

Key details: Max ADU size: 1,000 sq ft or 75% of home. ADUs per lot under 1 acre: 1 attached + 1 detached. ADU rear/side setback: 5 feet. Extra parking required: None. Review type: Ministerial, no public hearing.

An ADU built beyond the 1,000-square-foot or 75-percent cap, sited closer than the 5-foot rear or side setback, or proposed on tribal land or restricted airport-vicinity property is not eligible for ministerial approval and can be denied by the community development director; the applicant's only recourse for a denial is the Section 102-2 appeal to the board of adjustment.

Shed & Carport Rules

Sheds and other accessory structures in Surprise must sit on the same lot as the main house, keep at least 5 feet of separation from other structures, and stay out of easements and required setbacks, under City Code § 106-10.3. Table 106-10b caps most sheds' height at 9 feet, bars them from the front yard, and limits any single accessory structure to 3,000 square feet.

Key details: Min. structure separation: 5 feet from other structures. Shed side/rear setback: 5 feet. Shed front yard: Not allowed (with limited exceptions). Max height: 9 ft at setback, up to 15 ft. Per-structure size cap: 3,000 square feet, note 4.

Placing a shed or other accessory structure inside a required setback or easement, or building one before the primary residence exists, violates § 106-10.3 and is treated as a technical code violation, subject to civil or criminal penalties under § 105-25 for construction that does not conform to the approved building permit or a building official's directive; oversized structures beyond the 3,000-square-foot per-structure cap or a second detached garage beyond the one allowed under § 106-10.3(H) can be denied a permit or ordered removed.

The Bottom Line

Surprise's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Surprise is broadly strict or permissive.

This guide is based on Surprise's current municipal code. Local rules can and do change, so check the individual ordinance pages for the latest details, penalties, and FAQs.