Starting January 1, 2027, California homeowners can build two detached ADUs on a single-family lot instead of one. Governor Newsom signed AB 956 (Quirk-Silva) on September 29, 2026, and it is now Chapter 791, Statutes of 2026.
For Los Gatos and the rest of Silicon Valley, where lots are often large and housing is scarce, this is one of the most meaningful ADU changes in years. It affects what your property can become, what a buyer should look for, and how a seller can position a listing. Here is what the new California ADU law actually does, and what it doesn't.
What AB 956 Changes for California ADUs
Starting January 1, 2027, California homeowners can build two detached ADUs on a single-family lot instead of one. Governor Newsom signed AB 956 (Quirk-Silva) on September 29, 2026, and it is now Chapter 791, Statutes of 2026.
For Los Gatos and the rest of Silicon Valley, where lots are often large and housing is scarce, this is one of the most meaningful ADU changes in years. It affects what your property can become, what a buyer should look for, and how a seller can position a listing. Here is what the new California ADU law actually does, and what it doesn't.
What AB 956 Changes for California ADUs
Under current law, a single-family lot gets one detached, new-construction ADU through the state's streamlined (ministerial) approval path. AB 956 raises that to two. The key rules for those units:
Detached ADUs: up to two new-construction units on a lot with an existing or proposed single-family home.
Size: cities may cap each unit at 800 sq ft of livable space.
Height: 16 ft, or 18 ft near a major transit stop.
Side and rear setbacks: 4 ft.
Approval: ministerial, with no discretionary hearing. Permits and inspections still apply.
Rentals: terms must be longer than 30 days. This is not a short-term rental pathway.
The JADU trade-off. Once you build two detached ADUs this way, your city no longer has to approve a junior ADU (JADU) on the same lot. If you were planning a JADU inside the main house, run the numbers on both layouts first.
What it doesn't do. AB 956 does not split your lot. That is still an SB 9 process, and SB 9 parcels don't get the two-detached-ADU benefit. Stacking too many units through ADU law can also complicate a future SB 9 split, so think about long-term plans before you build.
New Limits on HOA and CC&R Restrictions
AB 956 also tightens California's protections against private rules that block ADUs. Civil Code sections 714.3 and 4751 now protect lots "zoned to allow" single-family use, not just lots "zoned for" it. That closes a loophole for single-family homes in zones that also permit other housing types.
HOAs can still impose reasonable restrictions on design and placement. But a covenant that effectively prohibits or unreasonably restricts a qualifying ADU is void. One caveat: condo owners gain nothing here, because the final bill dropped language that would have covered condominiums.
Why Two ADUs Matter in Los Gatos and Silicon Valley
Many Los Gatos properties, especially larger flat lots and estate parcels, have the backyard space for two cottages but were capped at one. That cap is gone. For homeowners, a second detached unit can mean:
Multigenerational living: a cottage for aging parents and another for an adult child, each with its own entrance and privacy.
Long-term rental income: two separate units on one property, rented for 30+ days.
Flexibility: a home office or guest house today, a rental or family unit later.
For buyers, lot size and layout just became more valuable. A property with a deep, accessible rear yard now has more built-in potential than it did a year ago. For sellers, that potential is a selling point worth showing, ideally with a simple site plan that illustrates where two units could go.
Hillside properties need a closer look. Slopes, easements, utility access and fire-safety rules in high fire hazard areas still apply, and they can limit what is actually buildable.
What to Do Before January 1, 2027
Measure your yard. Two 800 sq ft cottages with 4 ft side and rear setbacks need real space. Fire code governs spacing between buildings.
Map what already exists. An existing ADU, JADU or garage conversion changes the math. The state-guaranteed maximum is still four homes on the lot.
Budget for fees. ADUs of 750 sq ft or less pay no impact fees. Under SB 1117, signed the same day, larger units on lots with up to two ADUs pay fees only on space above 750 sq ft. Utility connection fees can still apply.
Check with the Town. Los Gatos and other cities will need to update local ADU ordinances. State law controls where they conflict, but confirm local filing steps before you submit.
Plan around timing. The law is not retroactive and takes effect January 1, 2027. It doesn't address applications already pending on that date.
This post is general information, not legal advice. Talk to an attorney about HOA disputes and to your design and construction team about feasibility on your specific lot.
Thinking About Adding ADUs in Los Gatos?
Whether you're buying a lot with ADU potential, selling a home whose backyard just became more valuable, or deciding what to build, I can help you see the full picture. My work connects real estate, design-build construction and organizing, so we can look at your property from purchase through move-in. Reach out to talk through what AB 956 could mean for your home.