Important Fees to Know for a 400 Sq Ft Garage Conversion in Santa Ana, CA

Converting a garage into a livable space in Santa Ana, California, can be an excellent way to create an Accessory Dwelling Unit (ADU) and boost your property’s value. However, many homeowners are surprised by the number and size of city fees involved in the process.
Here’s a real-world breakdown of the plan check fees, permit fees, and school fees for a recent 400 sq ft garage conversion project in Santa Ana.

Permit & Plan Check Fees

For this project, the initial step was pulling the building permits. The city charged $1,041 for the plan check and general permit issuance. This is the essential fee to begin the process, allowing the city to review your architectural drawings and ensure the design meets Santa Ana building codes.

Trade-Specific Permit Fees

In addition to the general permit, you will be required to pay for specific building trades involved in your conversion:

• Mechanical permit: $490
  Covers HVAC work such as heating, ventilation, and air conditioning installation.
• Electrical permit: $443
  Covers wiring, outlets, lighting, and panel upgrades for the new unit.
• Plumbing permit: $541
  Covers installation of water lines, drainage, and fixtures for kitchens or bathrooms.

Combined, these trade permits add up to approximately $1,474.

Total Permit Costs

When you add the general plan check fee ($1,041) to the trade-specific permit fees ($1,474), the total permit cost for this Santa Ana garage conversion comes to $2,515.
These are costs paid directly to the city before construction begins.

School Impact Fees

In California, new habitable square footage often triggers school impact fees, which help fund local education infrastructure.
For this 400 sq ft garage conversion, the school fee was $2,200—a significant portion of the total project fees.

Overall Cost Just for City Fees

When you combine permit fees ($2,515) and school fees ($2,200), the total cost paid to the city reached nearly $5,000—before any construction work even started.

Why These Fees Matter

Understanding these costs in advance is critical for budgeting your garage-to-ADU conversion. Homeowners in Santa Ana and other parts of Orange County should expect similar expenses, though exact amounts may vary based on project size, complexity, and the latest city fee schedule.

Working with an experienced California ADU design firm can help you streamline the permit process, ensure compliance, and avoid costly delays.

At Ataman Studio, we help homeowners with:

• Custom ADU floor plans tailored to local regulations
• Remodeling and conversion design for garages and other spaces
• Permit-ready documents to reduce approval times