Do you need a permit for an ADU in San Jose, 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 Jose before you build.
Check your exact lot
Setbacks depend on your zoning district, and a flood zone can change the permit answer. Enter your address to see both.
Permits a ADU can need in San Jose
| Permit | When it applies |
|---|---|
| Building permit | Every ADU needs a building permit and a final inspection before anyone lives in it. |
| Ministerial ADU approval | State law requires cities to approve or deny a complete ADU application within 60 days, without a public hearing, if it meets objective standards. |
| Floodplain development permit | If the lot is in a FEMA special flood hazard area, all development there needs a permit. |
Limits that apply citywide
| 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 |
Local details
- 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.
How to apply
- SJPermits.org
- San Jose Building Division
- Phone: (408) 535-3555
Questions people ask
- When does a ADU need a building permit in San Jose?
- Every ADU needs a building permit and a final inspection before anyone lives in it.
- Do I also need a zoning permit for an ADU in San Jose?
- State law requires cities to approve or deny a complete ADU application within 60 days, without a public hearing, if it meets objective standards.
- Where do I apply for a ADU permit in San Jose?
- Apply through SJPermits.org, or call (408) 535-3555.
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...