Converting a garage in Phoenix: what the permit actually requires

A garage conversion in Phoenix always requires a permit — there is no cosmetic version of this project, because you are turning unconditioned storage into habitable space. Before anything else gets decided, one question sets the entire rulebook: is the finished space a bonus room, or is it an ADU?

Bonus room or ADU — the fork that changes everything

If the conversion adds a kitchen, a bathroom, or a sleeping area, the City reviews it as an ADU, with everything that entails — a separate address, utility connections, and the full ADU size and setback rules. If it functions as an extension of the house itself — a den, an office, a playroom with no kitchen or added sleeping area — it follows the simpler addition-review path instead.

Get this settled before your designer draws anything. The floor plan, the utility runs, and the permit fee all depend on which category the space falls into, and reclassifying partway through a project means redrawing plans that were built around the wrong rulebook.

The parking you are removing

Phoenix's Zoning Ordinance § 702 requires two off-street parking spaces for a single-family home. A garage conversion removes at least one of those spaces, and the ordinance doesn't waive the requirement just because the space is now a room.

If the conversion is reviewed as an ADU, replacement parking is explicit: you need to provide it, and it cannot sit in the front setback. On the bonus-room path the requirement is less explicitly spelled out in the application, but it doesn't disappear — the two-space minimum still applies to the property, and it's one of the most commonly overlooked pieces of a garage conversion plan.

The fire separation, and a Phoenix amendment worth knowing

Building code sets a fire-separation standard for the wall and ceiling shared between a garage and the living space of a house, because a garage is treated as a higher fire-risk area than a bedroom or living room. Converting the garage doesn't remove that history — the assemblies still need to meet the standard for whichever wall is now interior.

Phoenix also adopted a 2024 amendment to Section R302.5.1 that matters here: no opening from a garage or carport may lead directly into a sleeping room, or into a hallway that serves only a sleeping room. If your conversion plan repurposes the old garage entry door as access to a new bedroom hallway, that detail needs to be resolved before permitting, not after.

Egress, if any part becomes a bedroom

Any new bedroom needs a code-compliant egress opening under Section R319 (renumbered from the old R310). The minimums are a 20-inch clear width, a 24-inch clear height, and a sill no higher than 44 inches above the finished floor.

Garages are rarely built with a window that already meets this, which means egress is often the detail that drives the entire floor plan of a bedroom conversion — where the window goes determines where the bed wall, the closet, and the door can go.

Get the full guide — $29

The 27-page Phoenix Garage Conversion Guide walks through the bonus-room-versus-ADU decision in detail, with diagrams for the parking and fire-separation requirements, the exact egress window dimensions, energy and electrical code triggers, the inspection sequence, guidance for legalizing an already-converted garage, and cost ranges by scope.

See also: ADU requirements · As-built drawings (free) · Remodel permit rules · Services