ADU rules in San Francisco, CA
Yes. Every ADU needs a building permit and a final inspection before anyone lives in it.
Rules last checked by a person on October 19, 2026. Guidance only; confirm with San Francisco before you build.
City and state limits
| Side setback (max a city can require) | 4 ftNo setback at all for an ADU inside an existing structure or rebuilt in the same footprint. |
|---|---|
| Rear setback (max a city can require) | 4 ft |
| Detached ADU height (minimum a city must allow) | 16 ft; 18 ft within 1/2 mile of major transit (+2 ft for matching roof pitch) or on a lot with a multistory multifamily building |
| Attached ADU height (minimum a city must allow) | 25 ft or the house's height limit, whichever is lower |
| Size a city must allow | At least 850 sq ft (1 bedroom) or 1,000 sq ft (2+ bedrooms) |
| Guaranteed regardless of lot coverage or FAR | 800 sq ft with 4 ft side and rear setbacks |
| Junior ADU | Up to 500 sq ft inside the house |
| Parking | No more than 1 space per unit or bedroom; none within 1/2 mile walk of transit |
| Owner occupancy | Cannot be required for an ADU (JADUs with shared sanitation excepted) |
| Impact fees | None for an ADU of 750 sq ft or less |
Good to know
- Call 811 at least a few days before you dig footings or post holes. Utility locating is free.
- HOA covenants and deed restrictions can be stricter than city rules. Check yours before you build.
Check your lot
Where to apply
- Check if your project needs a permit (sf.gov)
- SF Property Information Map
- Phone: (628) 652-3200
Sources
- HCD Accessory Dwelling Unit Handbook (March 2026). Checked 2026-10-19.
A setback of no more than four feet from the side and rear lot lines shall be required for an attached or detached ADU (Gov. Code, 66314(d)(7)).
- 44 CFR 59.1, definition of development (NFIP). Checked 2026-10-19.
Development means any man-made change to improved or unimproved real estate, including but not limited to buildings or other structures...
- 44 CFR 60.3, floodplain management criteria. Checked 2026-10-19.
Require permits for all proposed construction or other development in the community...