We’re working on resources to make it easier to build an ADU in Santa Clara County.
ADU Guidebook – your go-to guide for building an ADU, from inspiration through move-in
Comprehensive ADU website and Can I Build? address lookup tool
Browsable gallery of ADU plans for purchase
Stories of real ADUs built in your community
And more!
Accessory dwelling units (ADUs), also known as “granny flats,” “in-law units,” or “backyard cottages,” come in many shapes and sizes but are always a self-contained home that is smaller than the main dwelling and legally part of the same property. ADUs must have a kitchen and place to sleep, and can range from small studios under 500 square feet to a moderately sized home with multiple bedrooms.
JADU (Junior ADU)
Smaller unit of up to 500 square feet in a single-family home
Conversion
Converted space within a single-family home or accessory structure (like a garage)
Attached
A new unit attached to a single-family home (may include converted space)
Detached
New freestanding unit with a single-family home
Multi-family
A new detached, conversion, or attached unit with a multi-family building
There are many reasons to build an ADU — keeping multiple generations of family together on the same property, financial security, flexibility over time, safe and convenient housing for friends or local workers, and many others. Here are some of the reasons to build an ADU:
Space for adult children, aging relatives, or loved ones with special needs.
An extra set of eyes and hands on your property can be helpful for safety, when you travel, upkeep, and more.
ADUs help address housing challenges by adding homes that typically rent for less, allowing people to live and work in the same community.
Estimate the cost of converting part of your home or constructing a new ADU for all jurisdictions across Alameda County. You can even use the calculator to think through size, type of construction, rents, financing and return on investment (ROI) of building an ADU.
ADU SCC is an initiative of the Santa Clara County Planning Collaborative supported by the Cities Association.
