For many Santa Clara County buyers, the biggest challenge is finding a home that fits both their lifestyle and their budget. A smaller home in an established neighborhood could be appealing—but buying a backyard cottage separately from the main house has traditionally been difficult.
San José is helping change that conversation. Its ADU condominium program allows eligible accessory dwelling units to become separately owned homes after the required approvals.
What is an ADU?
An accessory dwelling unit is an additional home on a residential property, with its own living, cooking, and bathroom facilities. It might be a backyard cottage, an attached unit, or a converted space.
People often associate ADUs with rental income or housing for relatives. Separate ownership adds another possibility: a buyer purchasing the smaller home while someone else owns the primary residence.
What changed in San José?
California’s AB 1033 opened a pathway for cities and counties to authorize separate sales of ADUs as condominiums. San José adopted its implementing ordinance in 2024. The city’s guidance explains that qualifying permitted ADUs may be conveyed through an approved parcel map.
This is a condominium ownership arrangement. A detached cottage can look like a small house while legally being a condominium, with rights and obligations defined in the recorded documents.
Source: City of San José ADU condominium guidance
An idea that has already become reality
The city announced California’s first ADU condominium conversion in August 2025. A subsequent city release reported the first separate ADU condo sale, involving a 749-square-foot home near downtown.
Those milestones matter because they show this ownership model moving beyond a policy proposal. They do not mean every backyard home qualifies—or that a large supply of these properties is already available.
Source: City of San José first ADU condo sale announcement
Why buyers may find it appealing
A smaller property could offer an additional entry point into ownership for buyers who do not need a large home. Depending on the property, it may combine a neighborhood setting with a manageable floor plan.
A lower price than a larger nearby house is possible, but not guaranteed. Location, construction quality, outdoor space, financing, and ownership expenses all influence affordability.
Before purchasing, buyers should understand which areas belong exclusively to their unit, whether access or outdoor space is shared, and who pays for maintenance. They should also ask a lender to evaluate the specific condominium arrangement early.
What homeowners need to know
A permitted ADU does not automatically become separately saleable. The conversion involves a formal approval and recording process.
California’s housing department identifies requirements including a safety inspection, lienholder consent before recording, notification to utility providers, and compliance with condominium and subdivision laws. Properties in an existing planned development also require express written association authorization.
Owners should compare potential sale proceeds with conversion costs, financing consequences, and the effect on the remaining home. Selling the ADU also changes future control of the property.
Source: California HCD ADU Handbook, March 2026
What this means for Almaden Valley and Santa Clara County
For eligible properties within San José, including parts of Almaden Valley, this is an ownership option worth investigating. It could expand the range of smaller homes available in established neighborhoods.
The state law allows local adoption, so homeowners elsewhere in Santa Clara County should check their own jurisdiction’s current rules. A San José mailing address alone does not establish which agency governs a property.
ADU ownership will not solve the county’s affordability challenge by itself. It does offer another way to think about housing: a backyard home can potentially become someone’s first home.
If you are considering buying an ADU condominium or exploring a conversion, start with the property’s jurisdiction, permit history, ownership documents, and financing options. A careful review can help determine whether this emerging model fits your plans.