California ADU Law – October 2026
AB 956 is signed, but it is not in effect yet. Governor Newsom signed AB 956 on September 29, 2026 (Chapter 791, Statutes of 2026). It requires California cities to approve up to two detached ADUs on a single-family lot instead of one.
The new rule takes effect on January 1, 2027. Until then, today’s rules still apply: one detached ADU plus one junior ADU. Do not design or submit plans for two detached ADUs until you confirm how your city will apply the new law.
What Happened
On August 28, 2026, California YIMBY announced that the Legislature had passed AB 956 by Assemblymember Sharon Quirk-Silva (D-Fullerton) and sent it to the Governor. Many homeowners read that news as “two ADUs are now allowed.” That was not true yet: a bill that passes the Legislature can still be vetoed.
The next step came on September 29, 2026. Governor Newsom signed a housing package that included AB 956, listed in his announcement as “Accessory dwelling units and junior accessory dwelling units.” The bill was chaptered the same day as Chapter 791, Statutes of 2026.
So the honest status today is: AB 956 is law, but it does not take effect until January 1, 2027. California bills signed in a regular session take effect on January 1 of the following year unless they say otherwise.
What AB 956 Changes
- Two detached ADUs instead of one. Today, state law requires a city to approve one detached, new-construction ADU on a lot with an existing or proposed single-family home. AB 956 raises that to two. Cities must approve them ministerially, meaning by a checklist review with no public hearing and no discretionary denial.
- The junior ADU trade-off. If two detached new-construction ADUs are built on a lot, the city is no longer required to also approve a junior ADU (JADU) on that lot. The state-guaranteed maximum goes from “one detached ADU plus one JADU” to “two detached ADUs.”
- HOAs and CC&Rs. California already bars HOAs and deed restrictions from prohibiting or unreasonably restricting ADUs on single-family lots. AB 956 broadens those protections to cover both ADUs and junior ADUs, including in common interest developments. In the sponsor’s words, it makes sure HOAs “cannot block otherwise legal ADUs.”
- Single-family homes on land zoned for more. The protections used to cover lots “zoned for single-family residential use.” AB 956 changes that to lots “zoned to allow single-family residential use.” That covers a single-family home sitting on land zoned for apartments, which some cities had treated as outside the ADU rules.
California YIMBY, the bill’s sponsor, summed it up: “AB 956 strengthens and clarifies property rights and gives homeowners clear standards to build two detached ADUs on their properties.”
Why It Is Not a Done Deal for Your Backyard Yet
The bill is final. Your project may not be. Here is what still has to happen, and what can still trip you up.
1. Nothing changes until January 1, 2027
Until then, cities apply the current rules. If you submit plans today for two detached ADUs, the city is not required to approve the second one under state law. Some cities already allow more than the state minimum under their own local rules, but you need to confirm that before you pay for a design.
2. Your city has to catch up
The new law applies statewide, including in the City of Los Angeles and every other city in LA, Orange and Ventura Counties. But city ordinances, application forms and plan-check checklists usually lag behind state law. Cities including Irvine and Solana Beach formally opposed AB 956. Expect a period in early 2027 when plan checkers are still working out how to apply it, and keep a copy of the statute handy.
3. The details still matter
AB 956 changes how many detached ADUs a city must approve. It does not remove the other rules: height, setbacks, fire separation, utility connections, and site conditions like hillsides, easements or very high fire hazard severity zones. Lots in the Coastal Zone still go through coastal review. Two detached units also have to physically fit on your lot with legal access, and many lots simply do not have the room.
4. Losing the JADU option
If you plan to build two detached ADUs, the city no longer has to approve a junior ADU on the same lot. For some families a JADU (a small unit inside the main house) is the cheapest way to add a unit. Run the numbers on both layouts before you commit.
What This Means for LA Homeowners
Starting in 2027, a typical single-family lot can carry the main house plus two separate backyard homes. That is a big shift in what a lot is worth to an investor or a multigenerational family. Combined with AB 1033, which lets cities allow an ADU to be sold separately as a condo, the backyard is becoming one of the most valuable parts of an LA property.
If you are planning an ADU now, the smart move is to plan for the 2027 rules even if you build only one unit today:
- Place the first ADU so a second one still fits. A first unit set in the middle of the yard can block the second one forever.
- Size your utilities for two units. Upsizing the electrical service, sewer line and water meter once is far cheaper than trenching twice.
- Decide on timing. If you want two detached units, you may be better off finishing the design now and submitting after January 1, 2027. If you only need one unit, there is no reason to wait.
- Check your lot first. Our free ADU Eligibility Check and Zoning Lookup show your zoning, overlays and lot data before you spend money on plans.
A second ADU bill, SB 1117 by Senator Sabrina Cervantes (D-Riverside), was signed the same day. We will cover it in a separate post.
Frequently Asked Questions
Did AB 956 pass?
Yes. The Legislature passed AB 956 in late August 2026, and Governor Newsom signed it on September 29, 2026. It became Chapter 791, Statutes of 2026.
Can I build two detached ADUs in California right now?
Not under state law yet. AB 956 takes effect on January 1, 2027. Until then, state law requires cities to approve one detached new-construction ADU plus one junior ADU on a single-family lot. Some cities allow more under their own rules, so check with your city or with us before you design.
Can my HOA stop me from building an ADU under AB 956?
California law already bars HOAs from prohibiting or unreasonably restricting ADUs, and AB 956 broadens those protections to cover ADUs and junior ADUs in common interest developments. An HOA can still apply reasonable rules, as long as they do not effectively block a unit that state law allows.
Do I lose the junior ADU if I build two detached ADUs?
Under AB 956, a city is not required to approve a junior ADU on a lot where two detached new-construction ADUs have been built. You can choose two detached ADUs, or one detached ADU plus a junior ADU, but the state only guarantees one of those combinations.
Does AB 956 apply in the City of Los Angeles?
Yes. State ADU law applies in every California city and county, including Los Angeles. Expect LADBS and LA City Planning to update their ADU guidance and forms around the January 1, 2027 effective date.
Planning an ADU for 2027?
We will check whether your lot can fit two detached ADUs, how to place the first one so the second still fits, and whether to submit now or after January 1, 2027.
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Or start with our free tools: ADU Eligibility Check • Zoning Lookup • Permit Lookup
Sources
- California YIMBY – “California Legislature Votes to Allow Homeowners to Build Two ADUs” (August 28, 2026)
- Office of the Governor – “Governor Newsom signs housing legislation” (September 29, 2026)
- CalMatters Digital Democracy – AB 956 bill status and history
- City of Irvine – Notice of Opposition to AB 956 (June 15, 2026)
Related Reading
- California 2026 ADU Laws Guide – the rules in effect until AB 956 kicks in.
- ADU Setback and Height Rules in Los Angeles – what still limits where a second unit can go.
- ADU ROI by City – rent, build cost and cash flow across Southern California.
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