Garage Conversion in Santa Ana, CA: Cost, Permits & Rules (2026)

A garage conversion is usually the lowest-cost path to an ADU in Santa Ana — $90,000-$180,000, versus $180,000-$400,000 for a new detached build — because the shell already exists.

Garage Conversion Cost in Santa Ana

Converting an existing garage in Santa Ana runs $90,000-$180,000. That's well under the $180,000-$400,000 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 Planning Division FY2026-27 fee schedule (effective July 1, 2026): Accessory Dwelling Unit Review $1,940; ADU Over-the-Counter Review $594; ADU Pre-Approved Plan Review $524; Minor Exception (appeal of a denial) $3,579. A 7% technology fee is added to all Planning, Building and Public Works applications, plan checks and permits, and card payments carry a 2.5% processing fee. Building Safety has no ADU-specific line: the FY2026-27 fee schedule (Section X) charges structural plan check and inspection per sq ft by project type, for example $1.42/sq ft plan check for a single-story residential single-family structure ($3.14 two-story) plus $0.81/sq ft inspection, or $1.78 plus $1.42 per sq ft for a first-floor residential addition up to 500 sq ft, with electrical, plumbing and mechanical items priced separately; ask Building Safety at (714) 647-5800 which lines apply to your unit. Public Works: sewer connection fee $53 per plumbing fixture unit and a water capacity fee of $930 for a new 5/8-inch meter (FY2026-27 Public Works summary). A converted unit rents for about $2,250-$2,600/mo (1BR) in Santa Ana.

The Santa Ana Garage Conversion Permit Process

A garage-to-ADU conversion in Santa Ana needs building permits even if the exterior is unchanged. Approval process: Ministerial: the Executive Director of the Planning and Building Agency approves or denies an ADU or JADU once the application is complete, the unit meets every standard and the planning review fee is paid; incomplete or non-conforming applications are rejected rather than corrected (41-194.2(B)). Since July 1, 2026 every plan and application is filed online through the Accela Citizen Access (ACA) portal; paper is no longer accepted. In order: 1) confirm zoning, FEMA flood zone (A/AE) and historic status on the Property Information tool; 2) Planning Division ADU review: signed application and affidavit, ADU/JADU code-compliance form, a dimensioned PDF plan set (site plan at 1 inch = 20 ft, floor plans, elevations with height, roof plan, window schedule, landscape plan, lot legend with coverage) and a grant deed or six-month title report for new ground-floor area; single-family lots outside historic districts qualify for the over-the-counter track ($594), everything else goes through standard review ($1,940); 3) record the JADU owner-occupancy covenant if you are building a JADU; 4) Building Safety plan check plus Public Works review, filed together in ACA; a new detached ADU needs a grading permit unless it qualifies for the grading waiver (1,200 sq ft or less, under 50 cubic yards of cut and fill, not in flood zone A/AE); 5) pay permit, capacity and school-district fees (school fees are paid at the district) and pull the permit; 6) schedule inspections in ACA by 3 p.m. for the next business day. A denial can be appealed as a minor exception under Article V (41-194.6; $3,579 application fee) The review timeline is 60 days from a complete application for the city to approve or deny, or the ADU is deemed approved (Gov. Code 66317(a)(3), SB 543, in force since January 1, 2026); the clock is tolled if you request a delay. The city publishes no shorter target for standard review. For a pre-approved plan the city says an over-the-counter submittal 'may be approved in as little as one day' when complete and code-compliant (wording that predates the July 2026 move to online filing); confirm the current turnaround with Planning, with plan check: Electronic plan check through the Accela Citizen Access portal for Planning, Building Safety and Public Works together; detached ADUs on single-family lots and ADU conversions are on the city's E-Plan eligible list. The city's ADU code-compliance form asks for a transit proximity map if you claim the half-mile parking exemption, the water heater inside the ADU footprint, no exterior washer or dryer, underground utilities (SAMC 41-626), a landscaped front yard (SAMC 41-240), and windows, roof and finishes compatible with the main house (Citywide Design Guidelines). Fire sprinklers are required only if the main house is sprinklered (Gov. Code 66314(d)(12)); OCFA reviews sprinkler plans. A new detached ADU needs a grading permit or the signed grading waiver (form PCC-20), and a separate address. Pre-approved plans: Yes. The city offers 10 free downloadable pre-approved plan sets for detached ADUs: three 399 sq ft studios (Ranch, Spanish, Traditional), three 499 sq ft one-bedrooms (Ranch, Spanish, Traditional), a 625 sq ft one-bedroom Contemporary, a 677 sq ft one-bedroom Craftsman and a 677 sq ft one-bedroom Spanish, and a 749 sq ft two-bedroom Contemporary; every set stays within the 750 sq ft impact-fee exemption. Planning review drops to $524. Eligibility: a lot with an existing or proposed single-family home, outside FEMA flood zones A and AE, outside the French Park (SD-19), Downtown and Floral Park historic districts and Heninger Park (SD-40), and able to meet the grading-permit exemption. Submit the site plan, completed cover sheet, application and affidavit, hold-harmless agreement, grading waiver and a six-month title report; the city asks for a pre-submittal consultation via planning@santa-ana.org.

1. Confirm eligibility — ADUs are allowed in Any zoning district where residential or mixed-use development is permitted (SAMC 41-194.2(A)): R1 Single-Family, R2 Two-Family, R3 Multiple-Family, R4 Suburban Apartment, and Specific Development (SD) and Specific Plan areas that allow residential. The lot must have an existing or proposed home. Check your district with the city's Property Information search tool.
2. Prepare conversion plans — layout, egress windows, insulation, ventilation, smoke/CO detectors, plus a kitchen and bathroom.
3. Submit for plan check — Electronic plan check through the Accela Citizen Access portal for Planning, Building Safety and Public Works together; detached ADUs on single-family lots and ADU conversions are on the city's E-Plan eligible list. The city's ADU code-compliance form asks for a transit proximity map if you claim the half-mile parking exemption, the water heater inside the ADU footprint, no exterior washer or dryer, underground utilities (SAMC 41-626), a landscaped front yard (SAMC 41-240), and windows, roof and finishes compatible with the main house (Citywide Design Guidelines). Fire sprinklers are required only if the main house is sprinklered (Gov. Code 66314(d)(12)); OCFA reviews sprinkler plans. A new detached ADU needs a grading permit or the signed grading waiver (form PCC-20), and a separate address.
4. Pull permits and build — fees run Planning Division FY2026-27 fee schedule (effective July 1, 2026): Accessory Dwelling Unit Review $1,940; ADU Over-the-Counter Review $594; ADU Pre-Approved Plan Review $524; Minor Exception (appeal of a denial) $3,579. A 7% technology fee is added to all Planning, Building and Public Works applications, plan checks and permits, and card payments carry a 2.5% processing fee. Building Safety has no ADU-specific line: the FY2026-27 fee schedule (Section X) charges structural plan check and inspection per sq ft by project type, for example $1.42/sq ft plan check for a single-story residential single-family structure ($3.14 two-story) plus $0.81/sq ft inspection, or $1.78 plus $1.42 per sq ft for a first-floor residential addition up to 500 sq ft, with electrical, plumbing and mechanical items priced separately; ask Building Safety at (714) 647-5800 which lines apply to your unit. Public Works: sewer connection fee $53 per plumbing fixture unit and a water capacity fee of $930 for a new 5/8-inch meter (FY2026-27 Public Works summary); 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, inside the walls of an existing or proposed single-family home or its attached garage (41-194.1(5), 41-194.2(G)); minimum 220 sq ft. Needs an efficiency kitchen and its own exterior door; an interior door to the house is required only when the JADU shares a bathroom. One JADU per lot; lots with several detached houses or a multifamily building cannot have one 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.

Santa Ana Garage Conversion FAQ