Accessory Dwelling Unit (ADU) Permit in Thatcher, Arizona

Thatcher requires an accessory dwelling unit (adu) permit for: In all zoning districts where a single-family dwelling is an allowed use: one attached ADU AND one detached ADU permitted per lot where a primary dwelling exists; One additional detached ADU permitted on a lot one acre or larger IF at least one ADU on the lot is a restricted-affordable dwelling unit as defined by Arizona Revised Statutes; The largest ADU on a property is capped at 1,000 sq ft or 75% of the primary dwelling's size, whichever is less; any second/third ADU is capped at 600 sq ft or 50% of the primary dwelling's size, whichever is smaller; An attached ADU must be architecturally integrated into the primary dwelling's design (must not read as a duplex), though separate entries are allowed; ADU must be affixed to a permanent foundation and meet all applicable residential building codes — mobile homes and RVs are explicitly NOT acceptable as ADUs; ADU must always observe the primary dwelling's front-yard and street-side-yard setbacks; A detached ADU in the required rear yard needs a minimum 10-ft setback from a street-side rear property line and 3-ft setback from an interior rear/side property line; height capped at 18 ft in any required yard and must otherwise meet the zoning district's height rules; may not sit between the primary dwelling and the front property line; An attached ADU must comply with the same height regulations and setbacks as the primary dwelling; ADU must comply with applicable lot-coverage requirements (attached garages/porches/shade structures count toward lot coverage but not floor area); ADU must be subordinate to the primary single-family dwelling for all addressing and utilities. If your project isn't listed, confirm with Town of Thatcher Community Development/Engineering (Building Department) — administered jointly with Planning & Zoning under the Office of the Town Manager at 928-428-2290 before starting work.

In Thatcher, the published Building Permit Fee (ADU) is: Set by Town Council resolution — no fixed dollar figure is published. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Thatcher's published plan-review target for an accessory dwelling unit (adu) permit is 0–10 business days.

You'll need: iWorq Citizen Portal Building Permit Application; Site Plan Review Checklist – Single Residence. See the required-documents checklist on this page for details on each.

Thatcher requires 3 inspection(s) for an accessory dwelling unit (adu) permit, in order: Foundation/Footing, Framing, Final. Schedule each through Town of Thatcher Community Development/Engineering (Building Department) — administered jointly with Planning & Zoning under the Office of the Town Manager (928-428-2290).

Apply through Town of Thatcher Community Development/Engineering (Building Department) — administered jointly with Planning & Zoning under the Office of the Town Manager at 3700 W. Main St., PO Box 670, Thatcher, AZ 85552. Phone: 928-428-2290, email: mpayne@thatcher.az.gov. Office hours: Monday - Thursday, 7:00 a.m. - 6:00 p.m. (Town Hall 4/10 schedule, closed Fridays). Building Inspector: Mike Payne. All residential and commercial building, addition, remodel, outbuilding, pool, solar, electrical, gas, plumbing, sign, infrastructure, and underground-work permit applications are submitted online through the Town's iWorq Citizen Portal (thatcherpermitting.portal.iworq.net), which requires uploaded PDF plans and contractor licensing documentation; a Site Plan Review Checklist (2 copies, D-size 24"x36") must accompany building plans and the permit application to the Building Inspector.. Official information: https://www.thatcher.az.gov/departments/community-development-engineering.

Thatcher, 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 Thatcher independently recognizes and administers its own construction codes through the Community Development/Engineering Department (Building Inspector), under Chapter 150 of the Town of Thatcher Code of Ordinances. Source: Town of Thatcher Code of Ordinances, Chapter 150 (amlegal.com/codes/thatcheraz); Town of Thatcher Planning & Zoning page.; International Building Code (IBC), 2015 Edition, as amended, adopted by reference (§ 150.01). Local amendments: automatic fire sprinkler systems required for all new structures (or additions/alterations resulting in) total floor area exceeding 7,500 sq ft; maximum building height of 45 feet from grade to the highest point, or 30 feet from grade to the top of the highest outside wall; § 101.1 retitled 'Building Code of the Town of Thatcher'; § 110.3.7 (Energy Efficiency Inspections) deleted; Table 2304.10.1 amended to add a story-to-story tie fastening schedule item. Source: Town of Thatcher Code of Ordinances § 150.01 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; International Plumbing Code (IPC), 2015 Edition, as amended, adopted by reference (§ 150.02). Amendments: § 101.1 retitled 'Plumbing Code of the Town of Thatcher'; § 903.1 amended to insert '12' (inches). Source: Town of Thatcher Code of Ordinances § 150.02 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; National Electrical Code (NEC), 2014 Edition, published by the National Fire Protection Association, adopted by reference with no local amendments noted in the code text (§ 150.03). Source: Town of Thatcher Code of Ordinances § 150.03 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; International Mechanical Code (IMC), 2015 Edition, as amended, adopted by reference (§ 150.04). Amendments: § 101.1 retitled 'Mechanical Code of the Town of Thatcher'; § 504.8.2 (clothes dryer exhaust ducts) amended to prohibit screws/fasteners extending into the duct. Source: Town of Thatcher Code of Ordinances § 150.04 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; International Fire Code (IFC) and International Fire Code Standards, 2015 Edition, as amended, adopted by reference (§ 150.05), administered by the Building Official acting as Fire Marshal. Amendments: no new building permits for shake/wood shingle roofing except repair/replace of existing shake/shingle roofs or additions under 20% of existing floor area; violation-abatement lien procedure; § 101.1 amended to insert 'Town of Thatcher'. Source: Town of Thatcher Code of Ordinances § 150.05 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; International Residential Code (IRC), 2015 Edition, as amended, adopted by reference (§ 150.06). Amendments: § R101.1 amended to insert 'Town of Thatcher'; § 303.4 (Mechanical Ventilation) deleted; § 309.5, § R313.1, § R313.2 (fire sprinklers) changed from 'shall' to 'may' (i.e., NOT mandatory in Thatcher, unlike many other AZ jurisdictions); Chapter 11 (Energy Efficiency) deleted; § P2603.5.1 (Sewer Depth) revised to a flat 12-inch minimum below grade regardless of freezing conditions; §§ 3902.16 and 3902.17 (Arc-Fault Circuit-Interrupter Protection) deleted. Source: Town of Thatcher Code of Ordinances § 150.06 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; International Fuel Gas Code (IFGC), 2015 Edition, as amended, adopted by reference (§ 150.07). Amendments: § 101.1 retitled 'Fuel Gas Code of the Town of Thatcher'; § 614.8.2 (clothes dryer exhaust ducts) amended identically to the IMC § 504.8.2 amendment. Source: Town of Thatcher Code of Ordinances § 150.07 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; International Existing Building Code (IEBC), 2015 Edition, adopted by reference with no amendments noted (§ 150.08). Source: Town of Thatcher Code of Ordinances § 150.08 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; International Energy Conservation Code (IECC), 2009 Edition — explicitly RESCINDED by the Town ('is hereby rescinded, as it is no longer needed') (§ 150.09), consistent with the Town's deletion of IRC Chapter 11 (Energy Efficiency) and IBC § 110.3.7 (Energy Efficiency Inspections). Thatcher does not appear to enforce a distinct energy code beyond whatever baseline requirements remain embedded in the adopted 2015 IRC/IBC after those chapter deletions. Source: Town of Thatcher Code of Ordinances § 150.09 (Ord. 157-2009, Ord. 158-2009, Ord. 181-2017).; International Property Maintenance Code, 2015 Edition, as amended, adopted by reference (§ 150.10) — the only Chapter 150 code section carved out of the Class 1 misdemeanor penalty provision in § 150.99(B). Source: Town of Thatcher Code of Ordinances § 150.10 (Ord. 167-2011, Ord. 181-2017).; International Private Sewage Disposal Code, 2009 Edition — explicitly RESCINDED ('is hereby rescinded, as it is no longer needed') (§ 150.11). Source: Town of Thatcher Code of Ordinances § 150.11 (Ord. 133-2005, Ord. 181-2017).; International Urban-Wildland Interface Code, 2009 Edition (ICC/IAPMO) — explicitly RESCINDED ('is hereby rescinded, as it is no longer needed') (§ 150.12). Source: Town of Thatcher Code of Ordinances § 150.12 (Ord. 133-2005, Ord. 181-2017).; ICC A117.1-equivalent accessibility standards are incorporated via § 150.13 (effective June 1, 2005, per A.R.S. § 41-1492.03): standards/specifications applicable to public entities and to public accommodations/commercial facilities under Arizona's disability-access statute are incorporated into any building code adopted by the Town, applying to new construction and post-effective-date alterations. Source: Town of Thatcher Code of Ordinances § 150.13 (Ord. 133-2005).; Swimming Pool Safety Code, A.R.S. § 36-1681 (Arizona state statute governing residential swimming pool enclosures/barriers), cross-referenced directly by the Town's Zoning Ordinance § 13.10 rather than a separate local pool-barrier ordinance; where a conflict exists, the Zoning Ordinance states the state statute controls. Source: Town of Thatcher Zoning Ordinance (June 2013, as amended through Ord. 195-2024), Section 13.10.; Manufactured homes, mobile homes, and Recreational Vehicles (RVs) are explicitly barred from use as an accessory building/accessory dwelling unit in any zoning district (Zoning Ordinance § 13.8.B.11); ADUs must be affixed to a permanent foundation and meet all applicable residential building codes — mobile homes and RVs are not acceptable as ADUs (§ 13.8.A.2). Source: Town of Thatcher Zoning Ordinance, Section 13.8.. Local amendments apply — see the Thatcher overview page for the full list.

Yes, as of Ordinance No. 195-2024 (April 2024). One attached and one detached ADU are allowed per lot with an existing primary single-family dwelling in any zoning district where single-family use is allowed, subject to size caps (1,000 sq ft/75% of the primary home, whichever is less, for the largest ADU), setbacks, height limits, and a permanent-foundation requirement. Mobile homes and RVs cannot be used as ADUs.