San Jose, CA Accessory Structures: ADU Rules (2026)
ADU rules in San Jose, CA, also called accessory dwelling unit regulations or granny flat ordinances, cover setbacks, owner-occupancy, parking, and permit requirements.
Key Facts
- Max floor area
- 1,000-1,200 sq ft by lot size
- Side/rear setback
- 0 feet for new construction
- Height limit
- 18 ft one-story, 25 ft two-story
- Parking required
- None for the ADU itself
- Units on single-family lot
- 1 ADU plus 1 junior ADU
Summary
San Jose allows one accessory dwelling unit plus one junior ADU on any single-family lot by right, capping floor area at 1,000 to 1,200 square feet and requiring no side or rear setback under Municipal Code § 20.80.175.
b.One thousand (1,000) square feet for an Accessory Dwelling on a lot with an area of up to nine thousand (9,000) square feet.c.One thousand two hundred (1,200) square feet for an Accessory Dwelling on a lot with an area greater than nine thousand (9,000) square feet. [...] 3.Setbacks.a.Front setback: Front setback of the zoning district, unless such setback prohibits an eight hundred (800) square foot Accessory Dwelling Unit.b.Side setback: 0 feet.c.Rear setback: 0 feet.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 5 Update 3).
Full Breakdown
San Jose Municipal Code § 20.80.175 implements state ADU law (Gov. Code § 66314 et seq.) with local development standards. Single-family lots get one attached or detached ADU plus one junior ADU; multifamily lots get one ADU. Floor area is capped at 1,000 square feet on lots up to 9,000 square feet, 1,200 square feet above that, with no cap for converting an existing accessory structure into an ADU. Detached one-story units max out at 18 feet, two-story at 25 feet. Side and rear setbacks are zero feet for new construction, and no off-street parking is required for the unit.
Violations & Fines
Building an ADU larger than the 1,000/1,200 square-foot cap, encroaching into the required setbacks, or skipping the building permit exposes the structure to a stop-work order and possible removal until it complies or is permitted after the fact.
Frequently Asked Questions
Do I need extra parking for a San Jose ADU?
How big can a San Jose ADU be?
Sources & Official References
Other rules in San Jose
How San Jose compares: Easiest Cities to Build an ADU·California rules heatmap·Compare San Jose to another location·View the California accessory structures overview
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ADU Rules in Nearby Cities
How other cities in Santa Clara County handle adu rules.