Mechanical / HVAC Permit — Flagstaff, Arizona · Requirements sheet
Verified 2026-07-03 · Source: https://www.flagstaff.az.gov/DocumentCenter/View/90461/Revised-Over-Counter-Permit06102025
PermitBase is an independent reference and is not affiliated with any government agency. Requirements change and vary by project — confirm current details with the building department before you submit.
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
Review timeline
Inspection process
- 1
Rough-In
Ductwork and mechanical equipment rough-in before walls closed; gas piping pressure test before concealment
- 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
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.
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