ADU rules by city, each fact linked to an official city or state page and marked with the month we checked it. Where we could not verify something, the page says so.
Los Angeles, CA5 city-specific topics sourced + state lawSan Diego, CA7 city-specific topics sourced + state lawSan Jose, CA3 city-specific topics sourced + state lawSan Francisco, CA5 city-specific topics sourced + state lawOakland, CA2 city-specific topics sourced + state lawSacramento, CA3 city-specific topics sourced + state lawLong Beach, CA2 city-specific topics sourced + state lawSeattle, WA5 city-specific topics sourcedPortland, OR5 city-specific topics sourcedAustin, TX3 city-specific topics sourced
California baseline
Every California city must follow state ADU law. The short version, from the HCD ADU Handbook (March 2026):
- Size limits. State law: a city's maximum size must allow at least 850 sq ft, or 1,000 sq ft for more than one bedroom, and local rules cannot block an 800 sq ft ADU with 4 ft side and rear setbacks (Gov. Code 66321).
- Height. State law: detached ADUs get at least 16 ft; 18 ft within a half mile walk of a major transit stop or high-quality transit corridor (plus 2 ft to match roof pitch) or on a lot with a multistory multifamily building; attached ADUs up to 25 ft or the main home's limit if lower (Gov. Code 66321).
- Setbacks. State law: side and rear setbacks can be no more than 4 ft for new ADUs; converted existing space needs no new setback (Gov. Code 66314, 66323).
- Parking. State law: at most 1 space per ADU or per bedroom, whichever is less, and none within a half mile walk of public transit, in a historic district, within one block of a car share, or for ADUs inside the house (Gov. Code 66314, 66322).
- Owner occupancy. State law: no owner occupancy requirement for ADUs (Gov. Code 66315). A JADU requires the owner to live on site if it shares a bathroom with the main home (Gov. Code 66333).
- Permit steps and timeline. State law: the city must approve or deny a complete application within 60 days when there is an existing home on the lot (Gov. Code 66317).
- Fees. State law: no impact fees on ADUs of 750 sq ft or less; above that, impact fees must be proportional to the size of the main home. Plan check, permit and school fees can still apply.
HCD ADU Handbook (March 2026) checked Oct 2026
Coming next
We have not yet verified these cities, so we have not published pages for them: Fresno, CA, Bakersfield, CA, Riverside, CA, Anaheim, CA, Santa Ana, CA, Irvine, CA, Chula Vista, CA, Fremont, CA, Berkeley, CA, Pasadena, CA, Santa Monica, CA, Santa Rosa, CA, Denver, CO, Phoenix, AZ, Honolulu, HI.
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