Williams, 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 (A.R.S. Title 9). The City of Williams runs its own independent Building Department and adopts and administers its own construction codes; it does not defer building permitting to Coconino County. Source: City of Williams Building Department page (williamsaz.gov/departments_and_services/building_department); City of Williams Code of Ordinances Title 7, Chapter 7-1.; The City's currently codified adoption (Ordinance No. 956 / referenced in the code index as 'Ordinance No. 1007', adopted 10-27-2016, effective 1-1-2017) sets the 2015 editions of the International Building Code (IBC), International Residential Code (IRC), International Mechanical Code (IMC), International Plumbing Code (IPC), International Fire Code (IFC), International Fuel Gas Code (IFGC), International Property Maintenance Code (IPMC), and International Existing Building Code (IEBC), plus the 2014 National Electrical Code (NEC), each with City of Williams amendments layered on by article (e.g., Art. 1.02 amends the IBC, Art. 1.12 amends the IRC, etc.). Source: City of Williams Ordinance No. 956 (PDF, 'Adopted Building Codes Ordinance and Amendments'), Title 7, Chapter 7-1.; IMPORTANT CODE-CYCLE UPDATE FOUND: a separate, more recent 'Building and Design Criteria Submittal Requirements' document published directly on the City's Building Department page lists the DESIGN CODES as the 2024 editions of the IBC, IRC, IMC, IPC, IFC, IFGC, IPMC, and IEBC, plus the 2023 NEC and the Americans with Disabilities Act Accessibility Guidelines — this is a full code-cycle jump from the 2015/2014 cycle codified in Ordinance No. 956/1007. No corresponding new numbered ordinance repealing/replacing Ordinance No. 956 was found published in the American Legal Publishing code library or via Wayback Machine as of July 2026, but the City's own current-facing submittal-requirements document (undated but filename '2024 Design Criteria.pdf', hosted directly under the Building Department page alongside a 2024-cycle Solar Policy and 2025-dated fillable permit application forms) is the most current, most directly-published statement of which code edition the City is actually enforcing for new submittals as of this writing. Both the 2015-cycle codified ordinance and the 2024-cycle submittal-requirements sheet are cited throughout this record; where they conflict, the 2024 Design Criteria document is treated as controlling for current practice, with the codified Ordinance No. 956 amendments (administrative sections, fee/refund cross-references, permit expiration rules) still applicable since no repeal was found. Source: City of Williams 'Building and Design Criteria Submittal Requirements' (2024 Design Criteria.pdf); City of Williams Ordinance No. 956; Williams, AZ Code of Ordinances current through 2025 S-7 supplement (no Title 7 building-code ordinance number newer than 956/1007 appears in the codified index).; Chief Building Inspector / Building Official authority (Ordinance No. 956, Section 103.1 amendments to IBC/IRC/IMC/IPC/IEBC): the Department of Building Safety is created, headed by the Chief Building Inspector, and the terms 'Chief Building Inspector' and 'Building Official' are treated as one and the same throughout the adopted codes. Source: City of Williams Ordinance No. 956.; All buildings constructed or placed within city limits must meet the required Uniform Building Code (as locally adopted), except mobile homes and modular homes when specifically allowed by the Zoning Code. Source: Williams, AZ Code of Ordinances § 158.126 Building Permit and Plot Plan Required (Prior Code § 12-7.02; Ord. 747, passed 1995).; Building permit and plot-plan application procedure is governed by Code of Ordinances Chapter 154 (Development Procedures), § 154.018 Plot Plan and Building Permit: a plot plan and required fees are submitted to the City Planner; work within the Main Street District (including the Historic Preservation District) is forwarded to the Main Street Design Committee for review; each reviewing city department reviews plot plan applications on Monday and/or Tuesday of each week, ensuring staff review within six working days; the applicant then meets with the Chief Building Official, makes final changes, and submits four copies of the approved plot plan; a memorandum of agreement for public improvements (where applicable) must be signed before permit issuance; the applicant then submits a Building Permit Application and two sets of building plans to the Chief Building Official, which are reviewed by city staff or a referred architecture/engineering consultant, with the permit issued upon approval and fee payment. Source: Williams, AZ Code of Ordinances § 154.018 Plot Plan and Building Permit.; Commercial plans (new construction/alterations of 3,000 sq ft or more, major electrical/mechanical/plumbing improvements or replacements, housing of more than 4 units, or public improvements) must be sealed by a qualified Arizona-licensed architect and/or engineer per A.R.S. § 32-144; motels and restaurants additionally require a copy of approval-to-construct from the Coconino County Health Department (928-679-7120) before a City permit is issued. Source: City of Williams 'Procedure to Obtain Building Permit'.; Residential single-family detached structures are exempt from the Arizona Design Professional (architect/engineer stamp) requirement under A.R.S. § 32-121 et seq. unless circumstances dictate otherwise; duplexes/triplexes under 3,000 sq ft, two stories, or 20 total occupant load, with a single owner, may also be designed by a non-registrant. Sub-assemblies (roof trusses, manufactured floor beams) with imposed loading indicated may be submitted without a design-professional stamp. Retaining walls with unbalanced loading exceeding 4 feet must be designed by an Arizona-certified/registered design professional. Source: City of Williams Ordinance No. 956, IBC § 107.1 / IRC § R106.1.1 amendments.; Manufactured homes and mobile homes are permitted under Arizona's statewide Office of Manufactured Housing licensing/installation-permit structure (Arizona Department of Housing) for factory-built construction standards, layered with City of Williams local zoning/site/plot-plan compliance review — the City's own Zoning Code (§ 158.126) explicitly carves mobile homes and modular homes out of the standard Uniform Building Code requirement 'when specifically allowed by this chapter,' i.e., subject to zoning-specific provisions rather than the general IBC/IRC track. Source: Williams, AZ Code of Ordinances § 158.126; Arizona Department of Housing, Office of Manufactured Housing, Installation Permits page.. Local amendments apply — see the Williams overview page for the full list.