Accessory Dwelling Unit (ADU / Guest House / Casita) Permit in Oro Valley, Arizona

Oro Valley requires an accessory dwelling unit (adu / guest house / casita) permit for: One attached or detached ADU permitted per single-family lot; ADU size may not exceed the size of the primary dwelling; Setbacks: front matches the primary dwelling's requirement; side 5 ft; rear 5 ft; minimum 5 ft separation between buildings; Building height subject to the same restrictions as the primary single-family dwelling in that zoning district; No additional parking required for the ADU; If located between the primary house and the front lot line: no separate garage/carport and no separate street-accessed driveway (must share the primary driveway); a separate driveway is allowed only if the ADU is in a side or rear yard; Exterior design, roof pitch, and finish material standards applicable to the primary dwelling do NOT apply to the ADU; A permit for the ADU cannot be issued until the primary residence has obtained its own permit and completed intermediate inspections; A mobile home, RV, or other moveable habitable space may not be used as an ADU. If your project isn't listed, confirm with Town of Oro Valley Community and Economic Development Department — Permitting Division at 520-229-4800 before starting work.

In Oro Valley, the published Building and Fire Permit Fee — Based on Valuation is: Same valuation-based table as the Residential Building Permit (Town of Oro Valley Building and Fire Permit Fees schedule). These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

The Town's Residential Permits page states plan review for an Accessory Dwelling Unit / Guest House / Casita is 10 to 20 business days.

You'll need: Building Permit Application (Customer Portal); Construction Documents (cover sheet, site plan, floor/foundation/framing plans, elevations, mechanical/plumbing/electrical plans). Depending on your project, Oro Valley may also ask for: Height Certification Letter. See the required-documents checklist on this page for details on each.

Oro Valley requires 4 inspection(s) for an accessory dwelling unit (adu / guest house / casita) permit, in order: Limits of Grading and Plant Salvage, Foundation/Footing, Framing, Final. Schedule each through Town of Oro Valley Community and Economic Development Department — Permitting Division (520-229-4800).

Apply through Town of Oro Valley Community and Economic Development Department — Permitting Division at 11000 N. La Cañada Drive, Oro Valley, AZ 85737. Phone: 520-229-4800, email: permits@orovalleyaz.gov. Office hours: Plans are submitted electronically through the Town's Customer Portal (SmartGov Community, twn-orovalley-az.smartgovcommunity.com). Over-the-counter review is available Thursday mornings, 8:00-10:30 a.m., for simple like-for-like reviews (HVAC replacement, window/door replacement, or a single-family home built from a previously-approved model on a mass-graded lot); reviewed first-come/first-served, one submittal per customer, up to 8 reviews available, limited to projects completable in about 15 minutes. Director: Paul Melcher (520-229-4847, pmelcher@orovalleyaz.gov). Building Official: Larry Merrell (520-229-4805, lmerrell@orovalleyaz.gov).. Official information: https://www.orovalleyaz.gov/Government/Departments/Community-and-Economic-Development/Services/Apply-for-a-Building-Permit.

Oro Valley, Arizona has adopted: Arizona has NO statewide mandatory building code floor for general construction — code adoption is a per-city/county authority under state enabling statutes (e.g., A.R.S. Title 9 for municipalities). The Town of Oro Valley independently adopts and administers its own construction codes through its Community and Economic Development Department / Permitting Division and does not defer to Pima County for permitting within Town limits. Source: Town of Oro Valley Apply for a Building Permit / Residential Permits pages.; As of the last direct Town publication of its 'Building Codes and Amendments' page (archived March 2025), the Town's codified adopted set was: 2018 International Building Code (IBC), 2018 International Energy Conservation Code (IECC), 2018 International Fire Code (IFC), 2018 International Fuel Gas Code (IFGC), 2018 International Mechanical Code (IMC), 2018 International Plumbing Code (IPC), 2018 International Property Maintenance Code (IPMC), 2018 International Residential Code (IRC), 2018 International Swimming Pool and Spa Code (ISPSC) amendments, 2017 National Electrical Code (NEC), and ICC A117.1-2009/2010 ADA standards for accessible design — all adopted December 5, 2018, effective January 4, 2019. This is also the code set reflected on the Town's Residential Permits and Commercial Permits pages as archived March 2025. Source: Town of Oro Valley 'Building Codes and Amendments' page, 2018 Codes and Amendments section (live, confirmed 2026-07-16 — this section is retained on the page for grandfathered permits alongside the post-adoption 2024 set; see next note) and Town of Oro Valley Residential/Commercial Permits pages (live, confirmed 2026-07-16).; CODE-CYCLE UPDATE, NOW CONFIRMED LIVE (2026-07-16): the Oro Valley Town Council voted unanimously on September 3, 2025 to adopt a set of nine 2024 International Codes (2024 IBC, IRC, IEBC — for the first time — IFC, IFGC, IMC, IPC, IPMC, and ISPSC) plus the 2023 National Electrical Code, effective January 1, 2026, while explicitly declining to adopt the 2024 International Energy Conservation Code and retaining the 2018 IECC. This was previously corroborated only by two secondary sources; the Town's own 'Building Codes and Amendments' page is now directly confirmed live and states verbatim: 'The Town of Oro Valley adopted the 2024 International Building Codes and the 2023 National Electric Code with local amendments on September 3, 2025, with an effective date of January 1, 2026 (Exception: 2018 IECC)' and lists a 'BUILDING CODE TRANSITION POLICY AND FAQs' section (grandfathering permits submitted before January 1, 2026 under the 2018 codes, per Ordinances 25-05 and 25-06) plus a '2024 Codes and Amendments' section itemizing all nine 2024 codes and the 2023 NEC with their own local-amendment PDFs. Because today's date (2026-07-16) is after the January 1, 2026 effective date, the 2024 code set (2018 IECC excepted) is now the Town's live-effective standard for new applications, subject to the transition policy's grandfathering rules for permits submitted earlier. Note: the earlier count of 'ten' 2024 codes (from the secondary sources) was one too many — the live primary source lists nine 2024-dated codes plus the 2023 NEC. Source: Town of Oro Valley 'Building Codes and Amendments' page, 'BUILDING CODE TRANSITION POLICY AND FAQs' and '2024 Codes and Amendments' sections (live, confirmed 2026-07-16); Citizen Portal AI news summary of the September 3, 2025 Oro Valley Town Council meeting; LOVE (Let Oro Valley Excel) community newsletter post, 'Town of Oro Valley Adopts Updated Building Codes,' published September 10, 2025.; Golder Ranch Fire District (GRFD), which provides fire protection for Oro Valley, has adopted the 2024 International Fire Code, and the Town's own fire-code amendments are aligned with GRFD's. Oro Valley has required automatic fire sprinklers in all commercial buildings for more than 20 years, independent of this code cycle change. Source: LOVE (Let Oro Valley Excel), September 10, 2025 post, citing Town/Fire District staff statements.; Manufactured homes, mobile homes, and factory-built buildings are regulated directly by the State of Arizona (A.R.S. § 41-4001 et seq., Arizona Department of Fire, Building and Life Safety / Office of Manufactured Housing) for construction/installation standards; the Town issues a separate permit for on-site placement, foundation/tie-down, and zoning compliance. Source: standard Arizona statutory framework referenced across Arizona home-rule jurisdictions (consistent with the pattern documented for other Arizona municipalities in this dataset).. Local amendments apply — see the Oro Valley overview page for the full list.

One attached or detached accessory dwelling unit is permitted on the same lot or parcel as a single-family dwelling, per Oro Valley Zoning Code Section 25.2.