General ADU Permit Requirements in California

General ADU Permit Requirements in California

1. Zoning Compliance

• Allowed in most residential and mixed-use zones.
• Single-family homes: Allowed 1 ADU + 1 JADU.
• Multi-family properties: May allow multiple ADUs (up to 2 detached, or internal conversions of unused space).

2. Size Limits

• Detached ADUs: Up to 1,200 sq. ft. regardless of lot size (unless local codes permit more).
• Attached ADUs: Cannot exceed 50% of the primary residence, up to 1,200 sq. ft.
• JADUs (Junior Accessory Dwelling Units): Maximum 500 sq. ft., must be within the existing footprint of a home.

3. Setbacks

• Verify your local municipal code for this information.
  

4. Height

• Up to 16 ft. for single-story detached ADUs.
• New laws now allow up to 18–20 ft. in some cases (e.g., near transit or multifamily zones).

5. Parking

• No additional parking required if:

Located within ½ mile of public transit.

In a historic district, or

Part of an existing structure (garage, basement, etc.)

• If required, tandem or driveway parking is acceptable.

6. Owner-Occupancy

• Not required for ADUs built between 2020 and 2025.
• Required for JADUs (owner must live in either the main home or JADU).

7. Separate Utilities

• Not always required; depends on local agency.
• Separate meters may be optional for ADUs.

8. Permitting

• Submit:

   

  Site plan, floor plans, elevations

  Title 24 energy compliance docs

  Local application forms.

 

At Effortless Architecture, we are ready to help you in every step of the way, from the pre-design, to the permit processing phase. Click here to schedule your free consultation today!