ADU Regulations in California (CA)
California is rated Easy for ADU construction with an ADU-friendliness score of 93/100 (Very ADU-Friendly). California has a statewide ADU law that sets baseline rules across all municipalities. No owner-occupancy requirement. No additional parking required for ADUs. California has the most permissive ADU laws in the US. Multiple bills (SB 9, AB 2221, AB 1033, AB 976) have expanded ADU rights since 2017. As of 2025, ADUs can be sold separately from the primary home via AB 1033. No owner-occupancy requirement. Cities cannot require parking for ADUs near transit. Pre-approved ADU plans available in many jurisdictions.
Full ADU Regulations Summary for California
| ADUs Allowed | Yes |
| Statewide ADU Law | Yes |
| Maximum ADU Size | 1,200 sq ft |
| Owner Occupancy Required | No |
| Parking Required | No |
| Minimum Setback | 4 ft |
| Permitting Timeline | 60 days max |
| Impact Fees | Exempt for ADUs under 750 sq ft |
| Long-Term Rental Allowed | Yes |
| Short-Term Rental (Airbnb) Allowed | No |
| Ease of Building | Easy |
ADU Regulations by City in California
ADU rules can vary by city even within the same state. While California's statewide law sets minimum standards, some cities have additional local provisions. Below are ADU details for 5 cities in California.
Los Angeles
LA allows ADUs on most single-family and multifamily lots. Pre-approved ADU plans available through the city. Standard Plan program speeds permitting to under 30 days.
San Francisco
ADUs allowed in all residential zones. Streamlined permitting. No parking required. ADUs exempt from density limits.
San Diego
ADUs allowed on all residential lots. Allows both attached and detached ADUs plus a Junior ADU (JADU) on the same lot.
San Jose
ADUs by right on single-family lots. Up to 1,200 sq ft detached. City waives impact fees for ADUs under 750 sq ft.
Sacramento
ADUs allowed on all residential lots. Sacramento waives most fees for ADUs. Pre-approved plans available.
How California Compares to Other States
Below is a comparison of California with five states that have similar ADU-friendliness scores. This comparison helps illustrate where California stands nationally.
| State | Score | Statewide Law | Parking Req? | Owner Occ? | Ease |
|---|---|---|---|---|---|
| California (CA) | 93 | Yes | No | No | Easy |
| Arizona (AZ) | 93 | Yes | No | No | Easy |
| Oregon (OR) | 93 | Yes | No | No | Easy |
| Colorado (CO) | 91 | Yes | No | No | Easy |
| Vermont (VT) | 95 | Yes | No | No | Easy |
| Washington (WA) | 96 | Yes | No | No | Easy |
Frequently Asked Questions About ADUs in California
Can I build an ADU in California?
Yes, ADUs are allowed in California. California has a statewide ADU law that requires local jurisdictions to permit ADUs on residential lots. This means your city cannot outright ban ADUs. The ease of building is rated "Easy" with a friendliness score of 93/100.
Do I need to live on the property to have an ADU in California?
No, California does not require owner occupancy for ADUs. You can rent out both the main house and the ADU, which maximizes rental income potential.
How big can an ADU be in California?
The state maximum ADU size in California is 1,200 square feet. Local jurisdictions may set lower limits. Some cities also limit ADU size to a percentage of the primary dwelling (e.g., 50%).
Do I need extra parking for an ADU in California?
No, California does not require additional parking for ADUs. This is a significant advantage, as parking requirements are often the biggest barrier to ADU construction on smaller lots.
Can I rent out my ADU in California?
Yes, long-term rentals of ADUs are allowed in California. However, short-term rentals (like Airbnb) of ADUs are restricted in California. You can rent your ADU for long-term tenants but not as a vacation rental.
How long does it take to get an ADU permit in California?
The permitting timeline in California is: 60 days max. The statewide law sets maximum review periods that cities must comply with. Actual timelines can be affected by plan review backlogs, inspection scheduling, and the complexity of your project. Pre-approved ADU plans, where available, can significantly speed up the process.
Check ADU Rules for Your City
Use our ADU regulations lookup tool to find the specific rules for your city in California, or browse all 50 states to compare ADU regulations across the country. Remember that local rules may be more specific than state-level regulations.