Accessory dwelling unit permit cost — Tempe, AZ

Last updated: September 24, 2026

What affects the price

Building an ADU involves several moving parts that shape your total investment. The final figure depends heavily on whether you choose a prefab unit or a custom build from the ground up. Site conditions are another major factor; if your property requires extensive grading, utility trenching, or foundation work, costs will climb. You also have to consider your choice of finishes, like high-end appliances or custom cabinetry. Navigating local permit fees and impact assessments also adds to the total.

Frequently asked in Tempe

Also serving nearby: Chandler · Gilbert · Mesa · Phoenix · Glendale

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More on this: HUD ADU resources — ADU policy and financing research.

Service area details

Serving all of Tempe — population 189,834; about 4,748 residents per square mile across 40.0 sq mi. ZIP codes covered include 85280, 85281, 85282, 85283, 85284, 85285, 85287, 85288.

Neighborhoods served in Tempe: Downtown Tempe, ASU Area, Papago Park, South Tempe, University Heights — and every surrounding area.