A garage conversion is usually the lowest-cost path to an ADU in Riverside — $75,000-$130,000, versus $170,000-$280,000 for a new detached build — because the shell already exists.
Garage Conversion Cost in Riverside
Converting an existing garage in Riverside runs $75,000-$130,000. That's well under the $170,000-$280,000 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 $3,000-$9,000 typical (building permit + plan check); impact fees scale for units over 750 sq ft. A converted unit rents for about $1,300-$1,700 (1BR) in Riverside.
The Riverside Garage Conversion Permit Process
A garage-to-ADU conversion in Riverside needs building permits even if the exterior is unchanged. Approval process: Submit to the City of Riverside CEDD/Building & Safety; Permit-Ready ADU plan sets available to shorten design review The review timeline is ~3 business days initial review for Permit-Ready plans; longer for custom designs, with plan check: Fast with the City's Permit-Ready ADU plans. Pre-approved plans: Yes — City of Riverside Permit-Ready ADU Plans (CEDD): four plan types (746, 800, 1,020, 1,200 sq ft).
- Confirm eligibility — ADUs are allowed in Most residential zones (R-1, R-2, R-3, multifamily).
- Prepare conversion plans — layout, egress windows, insulation, ventilation, smoke/CO detectors, plus a kitchen and bathroom.
- Submit for plan check — Fast with the City's Permit-Ready ADU plans.
- Pull permits and build — fees run $3,000-$9,000 typical (building permit + plan check); impact fees scale for units over 750 sq ft; then framing, electrical, plumbing, and final inspection.
No Replacement Parking Required
No. California law (AB 68 / Gov Code §66314) prohibits cities from requiring replacement parking when you convert or demolish a garage to build an ADU — so you do not need to add a parking space anywhere on the lot. Owner-occupancy is not required, so you can rent the converted unit out.
The JADU Option for an Attached Garage
If your garage is attached to the house, you can convert it into a junior ADU (JADU) — capped at 500 sq ft and built within the existing walls. JADUs are cheaper and faster to permit than a full ADU, though they may share sanitation with the main home. A full ADU gives you more size and a separate unit; a JADU is the budget route.
Get Free ADU Quotes in Riverside
Tell us about your project and we'll connect you with ADU builders serving Riverside. Free, no obligation — you choose who to work with.
🔒 Your info is secure. We share it only with contractors quoting your project. No spam, no obligation.
Riverside Garage Conversion FAQ
How much does a garage conversion cost in Riverside?
Do I need a permit to convert a garage in Riverside?
Do I have to replace the parking if I convert my garage in Riverside?
How long does a garage conversion take in Riverside?
Can I convert an attached garage into a JADU in Riverside?
Compare your options: see the full Riverside ADU rules, estimate your build with the Riverside ADU cost calculator, or read the general garage conversion guide.