See what you can build in your backyard.
Enter your San José address. We read your lot and zoning from city records, apply City and State ADU rules, and show every option that fits.
- Free, no signup
- Official city records
- Results in seconds
From address to options in three steps
- Step 1
Enter your address
Pick your home from the city’s address list as you type.
- Step 2
We map your lot
Parcel boundary, zoning district, and flood, historic and wildfire overlays, straight from San José records.
- Step 3
See what fits
Each ADU type drawn on your lot with size, build cost, rent and yield. Change the house size and it updates instantly.
Four ways to add a home to your lot
Most single-family lots can have one ADU plus one Junior ADU. We check which of these your lot supports.
Detached cottage
Up to 1,200 sq ft
A standalone home in the backyard. Most privacy and the highest rent.
Garage conversion
Existing garage + 150 sq ft
Usually the fastest permit and lowest cost. No replacement parking needed.
Junior ADU
Up to 500 sq ft
A unit carved from your existing home. Good for family, and the owner lives on site.
Attached addition
850–1,000 sq ft protected
Shares a wall with your home and can go up to 25 ft, so two stories work.
San José ADU rules at a glance
San José lets you build under City standards or State standards. We check both and show you the better one.
- 1,200 sq ft
- Largest detached ADU under City standards on lots over 9,000 sq ft (1,000 sq ft on smaller lots).
- 4 ft
- Side and rear setback under State standards. City standards allow a one-story unit on the property line.
- 60 days
- For the city to approve or deny a complete ADU application.
- $0
- Impact fees on ADUs under 750 sq ft.
Rules last verified 2026-09-18. Always confirm with the city’s Planning Division before you design.
Find out what your lot can hold.
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