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Garage Conversion Guide

Garage Conversion in Phoenix, AZ: Cost, Permits & Rules (2026)

Turning your garage into a legal ADU is the cheapest, fastest way to add a rentable unit in Phoenix. Here's what it costs, what the permit takes, and the rules that matter.

$60,000-$140,000Typical Cost
60-90 daysPermit Timeline
NoneReplacement Parking

A garage conversion is usually the lowest-cost path to an ADU in Phoenix — $60,000-$140,000, versus $120,000-$240,000 for a new detached build — because the shell already exists.

Garage Conversion Cost in Phoenix

Converting an existing garage in Phoenix runs $60,000-$140,000. That's well under the $120,000-$240,000 typical cost of a ground-up detached ADU, because you're reusing the foundation, walls, and roof. The biggest variables are whether the slab and framing are sound, what utility/electrical upgrades are needed, and your finish level. Permit fees add $2,500-$4,200. A converted unit rents for about $1,250-$1,700/mo (1BR) in Phoenix.

The Phoenix Garage Conversion Permit Process

A garage-to-ADU conversion in Phoenix needs building permits even if the exterior is unchanged. Approval process: Building permit The review timeline is 60-90 days, with plan check: 2-3 weeks. Pre-approved plans: Limited availability.

  1. Confirm eligibility — ADUs are allowed in Single-family residential zones.
  2. Prepare conversion plans — layout, egress windows, insulation, ventilation, smoke/CO detectors, plus a kitchen and bathroom.
  3. Submit for plan check — 2-3 weeks.
  4. Pull permits and build — fees run $2,500-$4,200; then framing, electrical, plumbing, and final inspection.

Parking Rules for a Garage Conversion

No additional parking required (ARS 9-461.18 / AZ HB 2720 prohibits ADU-specific parking mandates) Garage conversions sometimes trigger different parking rules than new detached ADUs, so confirm replacement-parking requirements with Phoenix before you start. Owner-occupancy is not required, so you can rent the converted unit out.

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Phoenix Garage Conversion FAQ

How much does a garage conversion cost in Phoenix?

A garage conversion in Phoenix typically costs $60,000-$140,000 — well below the $120,000-$240,000 cost of a new detached ADU, because the foundation, walls, and roof already exist. Budget separately for permit fees ($2,500-$4,200) and any electrical or utility upgrades the conversion triggers.

Do I need a permit to convert a garage in Phoenix?

Yes. Converting a garage to a living unit in Phoenix requires building permits even if the exterior stays the same — the work has to meet code for insulation, egress, ventilation, electrical, and a kitchen/bathroom. The ADU permit timeline is 60-90 days, and the process is: Building permit

Do I have to replace the parking if I convert my garage in Phoenix?

No additional parking required (ARS 9-461.18 / AZ HB 2720 prohibits ADU-specific parking mandates) Garage conversions sometimes trigger different parking rules than new detached ADUs, so confirm replacement-parking requirements with Phoenix before you start.

How long does a garage conversion take in Phoenix?

Plan on 60-90 days for permit review (2-3 weeks for plan check), then construction. A garage conversion is usually faster to build than a ground-up ADU because the structure already exists.

Compare your options: see the full Phoenix ADU rules, estimate your build with the Phoenix ADU cost calculator, or read the general garage conversion guide.

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