SB 543: Faster, Clearer ADU Permitting in California
September 12, 20255 Conversations before building ADU
September 25, 2025California ADU Laws 2025: What Homeowners Need to Know
California continues to expand opportunities for homeowners to add Accessory Dwelling Units (ADUs)—commonly known as backyard homes, granny flats, or in-law suites. With new 2025 legislation, the process has become faster, more flexible, and more homeowner-friendly than ever before.
Key Changes Every Homeowner Should Know
Reduced Setbacks: Detached ADUs can now be built as close as 4 feet from the side or rear property line.
Generous Size Allowances: State law guarantees detached ADUs up to 800 sq ft and Junior ADUs (JADUs) up to 500 sq ft.
No Replacement Parking Required: If you convert a garage or carport into an ADU, cities cannot require you to replace that parking elsewhere.
Faster Approvals: Cities and counties must review ADU applications within 60 days of submission.
More Units Allowed on Multi-Family Properties: Apartment buildings and duplexes can now add additional ADUs beyond past limits.
New 2025 Laws
More Units on Multi-Family Lots: Up to 8 detached ADUs may be added in certain cases.
Amnesty for Unpermitted ADUs: Units built before 2020 can be legalized if they meet basic health and safety standards—without excessive penalties.
Streamlined Coastal Approvals: In many coastal communities, ADUs will no longer require a separate coastal development permit.
Why This Matters
ADUs are a vital part of California’s housing strategy. They give homeowners new options to:
Create rental income
Provide housing for family members
Boost property value
Help meet the state’s housing needs
With these streamlined rules, building an ADU has never been more practical.
