San Francisco runs two programs: a State ADU Program (Planning Code 207.2, ministerial review under state law) and a Local ADU Program (Planning Code 207.1).[1]
What is an ADU? An accessory dwelling unit is a small second home on the same lot as the main house: a backyard unit, garage conversion, attached addition or guest house with its own kitchen and bath.
California cities can set their own ADU rules, but never stricter than state law. Grey lines show the state floor from the HCD ADU Handbook.
| Size limits | Local program detached ADU: up to 850 sq ft for a studio or 1 bedroom, 1,000 sq ft for 2 or more bedrooms. Every ADU must be at least 220 sq ft with 7.5 ft ceilings.[2][4] 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).[5] |
|---|---|
| Height | Local program detached ADU: 16 ft. Converted space: no height limit; additions follow the zoning district.[2] 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).[5] |
| Setbacks | Local program detached ADU: 4 ft from side and rear lot lines. Converted space: no setbacks.[2] 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).[5] |
| Parking | No city-specific figure verified. The state minimum below applies; confirm local details with the city. 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).[5] |
| Owner occupancy | A JADU requires owner occupancy in the home or the JADU if they share a bathroom.[1] 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).[5] |
| Permit steps and timeline | Most ADU plans must be signed by a licensed design professional, with exceptions for small wood-frame homes. SF.gov lists hiring an architect at $10,000 or more. ADUs cannot be rented for less than 30 days.[4][3] 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).[5] |
| Fees | No city-specific figure verified. The state minimum below applies; confirm local details with the city. 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.[5] |
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Sources
Every fact above links to an official city or state page. Rules change; check the source before you build.
- [1] SF Planning: Accessory Dwelling Units checked Oct 2026
- [2] SF Planning: Local ADU comparison chart checked Oct 2026
- [3] SF Planning: Director Bulletin No. 3, State ADU Program checked Oct 2026
- [4] SF.gov: Design an ADU that meets City codes checked Oct 2026
- [5] HCD ADU Handbook (March 2026) checked Oct 2026