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Mechanical / HVAC Permit in Flagstaff, Arizona

Required for heating, ventilation, air conditioning, and related mechanical installations in Flagstaff, governed by the 2018 International Mechanical Code (IMC) and International Fuel Gas Code (IFGC) as adopted by the City of Flagstaff. Minor mechanical work can use the Over-the-Counter permit; rooftop unit replacements on structures over 50 years old or in historic overlay areas are routed to Current Planning for review.

Verified 2026-07-03 · Source

When you need this permit

  • Mechanical permit required for installation or relocation of furnaces, AC units, appliance vents, and similar mechanical equipment
  • Governed by the 2018 IMC and 2018 IFGC as adopted by City of Flagstaff (Resolution 2019-26 / Ordinance 2019-16)
  • Replacement and new rooftop units must be applied for as a full Building Permit and are routed to Current Planning for review if the structure is over 50 years old or in a historic overlay area
  • Apply through the Citizen Access Portal, or use the Over-the-Counter Permit Application for qualifying minor mechanical work

Required documents

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Fee schedule

Mechanical Over-the-Counter Base FeeCity of Flagstaff Over-the-Counter Permit Application (Rev. 06/10/2025); base fee plus itemized charges below
$29.90
Furnace <100,000 Btu, like-for-like replacementCity of Flagstaff Over-the-Counter Permit Application
$18.90
Furnace >100,000 Btu, like-for-like replacementCity of Flagstaff Over-the-Counter Permit Application
$23.20
Residential Air Conditioning UnitCity of Flagstaff Over-the-Counter Permit Application
$13.60
Appliance VentsCity of Flagstaff Over-the-Counter Permit Application
$9.25
Vent Fan connected to single ductCity of Flagstaff Over-the-Counter Permit Application
$9.25
Relocate FurnaceCity of Flagstaff Over-the-Counter Permit Application
$18.90
Install Suspended/Wall/Floor Mounted HeaterCity of Flagstaff Over-the-Counter Permit Application
$18.90
Wood/Pellet Stove/FireplaceCity of Flagstaff Over-the-Counter Permit Application
$18.90

Review timeline

Plan reviewFlagstaff’s published plan-review target
0–0 business days

How long did your Mechanical / HVAC Permit permit actually take in Flagstaff?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

  1. 1

    Rough-In

    Ductwork and mechanical equipment rough-in before walls closed; gas piping pressure test before concealment

  2. 2

    Final

    Equipment operational; clearances, combustion air, and venting verified

See the full Flagstaff inspection guide — scheduling & re-inspection fees →

Tips

  • A typical like-for-like furnace replacement under 100,000 Btu costs $29.90 base + $18.90 = $48.80 via the Over-the-Counter permit.
  • Rooftop AC/HVAC unit replacements on buildings over 50 years old or in a historic overlay require a full Building Permit routed to Current Planning, not the Over-the-Counter process.
  • reviewTimelineDays is 0 (no plan-review period): a qualifying Over-the-Counter mechanical permit is issued at the counter with no two-stage plan review. The City's ARS 9-835/9-836 timeframes documents (Residential Building Permits Plan Review Process and Timeframes; Commercial Plan Review) and the Over-the-Counter Permit Application itself contain no plan-review timeframe for OTC trade permits because they are not plan-reviewed. Only if the work requires a full Building Permit (e.g., a rooftop unit routed to Current Planning) is it reviewed under the 'Small Residential Plans' track (35 working days overall). Source: City of Flagstaff Over-the-Counter Permit Application (Rev. 06/10/2025) and Residential Building Permits Plan Review Process and Timeframes (PDF).

Frequently asked questions

Flagstaff requires a mechanical / hvac permit for: Mechanical permit required for installation or relocation of furnaces, AC units, appliance vents, and similar mechanical equipment; Governed by the 2018 IMC and 2018 IFGC as adopted by City of Flagstaff (Resolution 2019-26 / Ordinance 2019-16); Replacement and new rooftop units must be applied for as a full Building Permit and are routed to Current Planning for review if the structure is over 50 years old or in a historic overlay area; Apply through the Citizen Access Portal, or use the Over-the-Counter Permit Application for qualifying minor mechanical work. If your project isn't listed, confirm with City of Flagstaff Building Safety Section (Planning & Development Services, Community Development Division) at 928-213-2000 before starting work.

Via the Over-the-Counter permit process: $29.90 base fee plus $18.90 for a like-for-like furnace under 100,000 Btu (or $23.20 if over 100,000 Btu). Source: City of Flagstaff Over-the-Counter Permit Application (Rev. 06/10/2025).

Flagstaff's published plan-review target for a mechanical / hvac permit is 0–0 business days.

You'll need: Over-the-Counter Permit Application (PDF, Rev. 06/10/2025). See the required-documents checklist on this page for details on each.

Flagstaff requires 2 inspection(s) for a mechanical / hvac permit, in order: Rough-In, Final. Schedule each through City of Flagstaff Building Safety Section (Planning & Development Services, Community Development Division) (928-213-2000).

Apply through City of Flagstaff Building Safety Section (Planning & Development Services, Community Development Division) at 211 W Aspen Avenue, Flagstaff, AZ 86001. Phone: 928-213-2000, email: BuildingPermits@flagstaffaz.gov. Office hours: City Hall is open 8:00 am to 4:30 pm. Commercial permit attachments too large for the portal: Commercial.BuildingPermits@flagstaffaz.gov. Inter-departmental submittals: FrontCounter@flagstaffaz.gov.. Official information: https://www.flagstaff.az.gov/494/Building-Safety.

Flagstaff, Arizona has adopted: Arizona has no mandatory statewide building code edition — cities and counties each adopt and amend their own codes (per Arizona Revised Statutes framework for municipal building regulation; no state building-code-adoption agency parallel to Montana's DLI exists). The City of Flagstaff independently administers its own Building Safety program within city limits, separate from Coconino County's building department, which handles unincorporated county areas. Source: City of Flagstaff Building Safety page (flagstaff.az.gov/494/Building-Safety) and Building Permits page.; 2018 International Building Code (IBC) — adopted by City of Flagstaff Resolution 2019-26 and Ordinance 2019-16 on June 18, 2019, effective July 19, 2019 (the '2018 Suite of Codes'). Source: City of Flagstaff 2019 Adopted Building Codes (PDF); 2018 International Residential Code (IRC) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019; 2018 International Existing Building Code (IEBC) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019; 2018 International Mechanical Code (IMC) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019; 2018 International Plumbing Code (IPC) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019 (Arizona/Flagstaff uses the IPC, not the Uniform Plumbing Code); 2018 International Fuel Gas Code (IFGC) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019; 2018 International Energy Conservation Code (IECC) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019; 2018 International Swimming Pool and Spa Code (ISPSC) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019; 2018 International Solar Energy Provisions (ISEP) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019; a compilation of solar energy provisions from the IBC, IRC, IECC, IMC, IPC, IFC, and ISPSC; 2017 NFPA 70 / National Electrical Code (NEC) — adopted per Resolution 2019-26 / Ordinance 2019-16, effective July 19, 2019; ICC A117.1-2017, Accessible and Usable Buildings and Facilities — adopted per Resolution 2019-26 / Ordinance 2019-16; 1997 Uniform Housing Code, 1997 Uniform Administrative Code, and 1997 Uniform Code for the Abatement of Dangerous Buildings (ICBO) — retained as adopted codes per Flagstaff City Code Title 4, Chapter 4-01; All codes amended locally by Flagstaff City Code Title 4, Building Regulations (Chapters 4-01 through 4-11), on file with the City Clerk. Source: Flagstaff City Code Title 4 Building Regulations amendments document (2019 Amendments to the Adopted Codes, PDF, rev. 05/14/2019); Statewide overlay: Arizona Revised Statutes Section 9-468 sets mandatory statewide standards for solar photovoltaic and solar water heating construction permits (limits on required plan documentation, prohibits requiring a PE stamp absent a written justification, and caps solar permit fees at actual cost of issuance) — binding on the City of Flagstaff as a municipality. Source: azleg.gov ARS 9-468; Arizona Revised Statutes Sections 9-835 and 9-836 set statutory residential building-permit plan-review timeframes (Administrative Completeness Review and Substantive Review stages) that the City of Flagstaff's published review timeframes implement. Source: City of Flagstaff Residential Building Permits Plan Review Process and Timeframes (PDF). Local amendments apply — see the Flagstaff overview page for the full list.

Sources & verification

Verified against official sources. Last reviewed 2026-07-03.

Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Flagstaff building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.