Accessory Dwelling Unit (Casita) Permit in Tucson, Arizona

Tucson requires an accessory dwelling unit (casita) permit for: A permit is required for any ADU/casita — defined, like any dwelling unit, as having a place to sleep, a bathroom, and a kitchen; Two accessory dwelling units are permitted per parcel developed with a Family Dwelling (single-family home); a parcel developed with a duplex is permitted one accessory dwelling unit. A third ADU is allowed on a lot/parcel over one acre if at least one of the ADUs on that lot is a deed-restricted affordable unit (80% of area median income or less); Size: an ADU/casita is limited to 75% of the principal dwelling's gross floor area, not to exceed 1,000 sq ft of gross floor area OR up to 650 sq ft of gross floor area regardless of the principal dwelling's size, whichever is more permissive; Height: except as otherwise specified, an ADU/casita follows the dimensional standards of the principal (single-family) land use in the same zone — commonly a 25-foot height limit — rather than the lower 12-foot cap that applies to other accessory structures (accessory dwelling units are explicitly excepted from that 12-foot cap); Setback: minimum side and rear yard setback for an ADU/casita is 5 feet; A cool roof (high albedo level >60 SRI, or other cool roof technology per the ICC Green Construction Code) is required if the ADU/casita is built as a new structure; No vehicular parking is required to be provided for ADUs/casitas; ADUs are not required to match the exterior design, roof pitch, or finishing materials of the primary single-family dwelling on the same lot; ADUs/casitas are not subject to maximum residential density standards, and are exempt from being classified as a multifamily development or requiring a commercial site plan/commercial development standards when added to an established, occupied family dwelling; Both attached and detached ADUs must follow these Accessory Dwelling Unit standards (Tucson Unified Development Code (UDC) Section 6.6.3.B, as amended through Ordinance 12219, 12/16/2025); Permit includes zoning, building, and utility review as a bundled 'New Building/Dwelling, Development Package, Accessory Dwelling Unit' permit type; A dedicated Accessory Dwelling Unit checklist is published separately from the general New Dwelling and Addition/Alteration checklists; Falls under the Fast Lane (10-business-day performance goal) as 'Residential ADU / Casita'. If your project isn't listed, confirm with City of Tucson Planning & Development Services Department (PDSD) at (520) 791-5550 before starting work.

In Tucson, the published Building Permit Fee (valuation-based, same Construction Valuation Table as new construction) is: $89.45 minimum ($1-$2,000 valuation), scaling per the Building Permit Fees for New Construction table. Additional published fees: Digital Filing Fee — 1% of the total fee, minimum $18.54. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Tucson's published plan-review target for an accessory dwelling unit (casita) permit is 10–10 business days.

You'll need: Residential Building Permit Application Checklist - Accessory Dwelling Unit; Construction Drawings. See the required-documents checklist on this page for details on each.

Tucson requires 3 inspection(s) for an accessory dwelling unit (casita) permit, in order: Foundation/Footing, Framing, Final. Schedule each through City of Tucson Planning & Development Services Department (PDSD) ((520) 791-5550).

Apply through City of Tucson Planning & Development Services Department (PDSD) at Tucson Development Center, 201 N. Stone Avenue, 1st Floor, Tucson, AZ 85701. Phone: (520) 791-5550, email: PDSDinquiries@tucsonaz.gov. Office hours: Tucson Development Center, 201 N. Stone Avenue, 1st Floor: Mon.-Thur. 8 a.m.-4 p.m. (closed Fridays). Staff available by email/phone Mon.-Fri., 8 a.m.-4:30 p.m.. Official information: https://www.tucsonaz.gov/Departments/Planning-Development-Services.

Tucson, Arizona has adopted: Arizona has no mandatory statewide building code — code adoption is entirely a local (city/county) decision. The City of Tucson adopts its own model building codes, published by the International Code Council (ICC) and the National Fire Protection Association (NFPA), on a six-year cycle, with local amendments authorized by Ordinance #12171. Source: City of Tucson Planning & Development Services, Building Codes page (tucsonaz.gov/Departments/Planning-Development-Services/Codes/Building-Codes).; 2024 International Building Code (IBC) — effective January 1, 2026, as adopted by the City of Tucson with local amendments; 2024 International Residential Code (IRC) — effective January 1, 2026, as adopted by the City of Tucson with local amendments; 2024 International Existing Building Code (IEBC) — effective January 1, 2026; 2024 International Fuel Gas Code (IFGC) — effective January 1, 2026; 2024 International Mechanical Code (IMC) — effective January 1, 2026; 2024 International Plumbing Code (IPC) — effective January 1, 2026 (Tucson/Pima County use the International Plumbing Code, not the Uniform Plumbing Code); 2024 International Swimming Pool & Spa Code (ISPSC) — effective January 1, 2026; 2024 International Energy Conservation Code (IECC) — effective July 1, 2026 (the energy code follows the other 2024 model codes on a delayed effective date); 2023 National Electrical Code (NEC) — effective January 1, 2026; 2024 International Fire Code (IFC) — current adopted edition per City of Tucson Building Codes page; All permit applications and related submittals received on or after July 1, 2026 must comply with the 2024 International Codes and amendments as adopted by the City of Tucson and in effect as of that date, including the 2023 NEC where applicable. Applications submitted before July 1, 2026 continue to be reviewed under the code editions in effect at the time of submittal, unless approved by the Building Official. Source: City of Tucson Building Codes page.; Other adopted building regulations (updated less frequently than the six-year model code cycle): Arizona Administrative Code Title 18, Chapter 5 (Public and Semi-Public Swimming Pools); 2012 City of Tucson/Pima County Outdoor Lighting Code; ICC A117.1-2017 Accessible and Usable Buildings and Facilities (effective 1/1/26); Inclusive Home Design Ordinance. Source: City of Tucson Building Codes page.; Previously adopted (superseded) editions include the 2018 International Building/Residential/Mechanical/Plumbing/Fuel Gas/Existing Building/Swimming Pool & Spa Codes, 2017 NEC, and 2012-cycle International Codes with 2011 NEC. Source: City of Tucson Building Codes page.; Sustainability and related codes: City of Tucson Riparian Vegetation Preservation; Commercial Rainwater Harvesting (Engineering Code); EV Charging - Commercial and Multifamily (Zoning Code); Landfill Development Ordinance (Engineering Code); Native Plant Preservation Ordinance (Landscaping Code); Prohibition on Ornamental Turf (Zoning Code, UDC 7.6.4.D); WaterSense Plumbing Fixtures (Building Code). Source: City of Tucson Building Codes page.. Local amendments apply — see the Tucson overview page for the full list.

Two accessory dwelling units (casitas) are permitted per parcel developed with a single-family Family Dwelling (one per parcel with a duplex); a third is allowed on lots over one acre if at least one ADU is deed-restricted as affordable housing. Both attached and detached units must comply with Accessory Dwelling Unit zoning standards (UDC Section 6.6.3.B) — size capped at 75% of the principal dwelling's floor area (max 1,000 sq ft) or up to 650 sq ft regardless of the principal dwelling's size, a 5-foot side/rear setback, and the primary dwelling's zone height limit (commonly 25 feet). The permit bundles zoning, building, and utility review. Source: Tucson Unified Development Code Section 6.6.3 and City of Tucson PDSD Residential Permits page.