Buying a home with an ADU in California

California state-level rules buyers should know

• • Statewide right-to-build: every single-family lot can have at least one detached ADU and one JADU. Cities can't ban them outright.
• • Owner-occupancy: eliminated by AB 670 (2020) for new ADUs. Pre-2020 ADUs may still carry local owner-occupancy requirements — verify with the city for the specific permit.
• • Separate-sale: SB 1211 (effective 2024) allows ADUs to be sold separately under specific conditions in qualifying markets. Confirm parcel eligibility before relying on this.
• • Maximum size: 1,200 sq ft for detached ADUs as a guaranteed floor; cities can allow larger via discretionary review.
• • Setbacks: 4 ft side and rear setbacks are the statewide minimum; some cities have stricter local rules.

What to check when buying

• ✓ Pull the building permit history from the city's planning portal — should show a clean 'finaled' status.
• ✓ If permitted before 2020, verify whether the permit carries an owner-occupancy condition and whether the seller has been in compliance.
• ✓ For ADUs claimed to be eligible for separate sale, get SB 1211 eligibility confirmed in writing from the city's planning department.
• ✓ Check the rental status — long-term rentals are universally allowed; short-term (Airbnb-style) is restricted in San Francisco, LA, and a handful of other cities.
• ✓ Verify utilities: separate meters indicate income-property design intent and make rental compliance easier.

Permit info for California cities

The strongest signal of a legitimate ADU is a clean permit history at the city. Use these jurisdictional guides to cross-check what the seller's disclosure tells you.

• Permits in San Francisco
• Permits in Los Angeles
• Permits in San Diego
• Permits in San Jose
• Permits in Sacramento
• Permits in Oakland
• Permits in Berkeley

Related

• Full ADU buying guide
• ADU value analysis
• Verified ADU builders in California
• California permit overview
• LA cost guide
• San Diego cost guide