How to Get an ADU Permit in California

Although California state law (SB 9, SB 13, AB 68) supports ADU development statewide, each city and county can have its own zoning rules. Here's what to check:

• Minimum lot size

• Setback requirements

• Height limits

• Parking regulations

• Maximum square footage allowed

• Fire safety or utility access

🔍 Tip: Visit your city’s planning department website (e.g., LA, San Diego, San Jose) or call them directly to request an ADU zoning check for your property.

Getting an ADU permit in California can be technical and time-consuming. That’s why hiring a professional—such as an ADU architect, ADU designer, permit specialist, or general contractor—is highly recommended. These experts can help you:

• Prepare fully compliant plans

• Navigate the permitting process more efficiently

• Avoid common (and costly) mistakes

• Ensure your project meets all local and state regulations

If you're looking for a reliable expert, Fortune ADU is a great resource. They specialize in helping homeowners across California get their ADUs approved and built with less hassle. Their team understands the ins and outs of local codes, streamlining the process from design to permit approval.

You’ll need to prepare and submit detailed drawings and documentation that comply with California building codes. These usually include:

• Site plan – Showing the layout of your property and proposed ADU

• Floor plan – Interior layout of the unit

• Elevation drawings – Showing exterior views and heights

• Structural plans – Detailing materials, load-bearing walls, etc.

• Title 24 Energy Calculations – Required for energy efficiency compliance

All documents must meet the 2022 California Building Standards Code (Title 24), updated every three years (next update: 2025).

Submit your application and plans to your local Building and Safety Department. Depending on your city, this can often be done online via their permit portal.

You may need to include:

• Completed ADU permit application form

• Full construction plans

• Site surveys

• Permit fees (varies by city)

• Water/sewer service approval

• School district impact fee forms (if over 750 sq. ft.)

Once submitted, your plans go through a plan check phase, which may take 2–8 weeks.

The city may return your submission with corrections or requested changes. Don’t worry—this is a normal part of the ADU permit process.

Be ready to:

• Update your drawings

• Provide clarifications

• Adjust your design to meet setback or code requirements

A quick turnaround on corrections can keep your ADU project on schedule.

Once your plans are approved, you’ll be required to pay the ADU permit fees, which can range from $2,000 to $10,000+ depending on your project’s size, city, and complexity.

Fees typically include:

• Plan check fees

• Building permit fees

• Impact fees (may be waived for ADUs under 750 sq. ft.)

• School fees (if applicable)

• Utility connection fees

Good news:

Many California cities are waiving or reducing impact fees for ADUs under state-mandated reforms.

With your permit in hand, you’re ready to begin building an ADU in California. Make sure your contractor schedules required inspections throughout construction, including:

• Foundation inspection

• Framing and rough plumbing/electrical

• Insulation and drywall

• Final occupancy inspection

Skipping inspections can delay your Certificate of Occupancy.

After construction is complete, schedule a final inspection. If everything passes, you’ll receive a Certificate of Occupancy (CO) from your local building department.

This document makes your ADU legal to rent out or live in.

Once your ADU is permitted and approved, you might want to:

• List it for rent (short-term or long-term, depending on city rules)

• Register it as an official rental unit

• Claim potential tax benefits

• Update your homeowner’s insurance policy