THINKING: housing

AB 956: Two detached ADUs at Single Family homes and limits on HOAs

Published September 28, 2026

AB 956 increases the number of detached ADUs allowed on a single-family parcel from 1 to 2 and prohibits California HOAs from blocking legal ADUs. If signed by Governor Newsom, the bill will go into effect January 1st, 2027.

How many ADUs can I add to my property under AB 956?

AB 956 would amend CA Gov code section 66323 to allow up to 4 ADUs at single-family properties: 1 JADU, 1 conversion ADU and 2 detached ADUs. As it currently stands, the state code only permits 1 detached ADU at a single-family parcel, along with a conversion unit and a JADU.

The bill’s amended code text is shown below in bold:

“(a): Notwithstanding Sections 66314 to 66322, inclusive, a local agency shall ministerially approve an application for a building permit within a residential or mixed-use zone to create any of the following units, or, except as provided in subdivision (b), any combination of the following units:

(1) One accessory dwelling unit and one junior accessory dwelling unit per lot with a proposed or existing single-family dwelling…

(2) ~~One~~ Two detached, new construction, accessory dwelling units that ~~does~~ do not exceed four-foot side and rear yard setbacks for a lot with a proposed or existing single-family dwelling.

(b) A local agency is not required to ministerially approve an application for a building permit to create a junior accessory dwelling unit on the same lot where two detached, new construction, accessory dwelling units have been constructed.”

Project sequencing for 4 ADUs

To be able to add all 4 state exempt or “66323” ADUs, add a JADU before seeking approval for 2 detached ADUs. The stipulation created in section (b) is not specified in reverse: AB 956 does not explicitly preclude ministerial approval in a scenario where 2 detached ADUs are proposed with an existing JADU.

But, keep in mind AB 956 has yet to be signed into law, so this is an untested interpretation of the bill. Local jurisdictions may push back.

If the JADU has its own bathroom facilities, the primary residence is also no longer required to be owner occupied thanks to AB 1154 (2025). This amendment makes JADUs possible for small developers who may not currently live on site or want the flexibility to move out later on.

Unlocking an extra ADU

In certain cities, an additional local or “66314” ADU can be built for a total of 5 ADUs at a single-family property. According to California HCD’s ADU handbook, jurisdictions with an adopted ADU ordinance under CA Gov code 66314, may also allow at least 1 local standard ADU. This ADU would be subject to their established objective development and design standards.

Developers and owners interested in maximizing their site’s potential should take note of the following sequence:

If applicable, build a local “66314” ADU first. This ADU must follow local FAR, setback and yard requirements. As a result, this ADU will take up more space on a parcel, so squeezing it in later on can prove infeasible.
Propose 1 conversion ADU and 1 JADU (subject to applicable owner occupancy requirements if the bathroom is shared with the primary residence).
Add 2 detached ADUs when AB956 is written into law.

In practice, 5 ADUs are likely only possible on larger parcels. Fire separation distance between structures is the constraint that most often rules out a unit on a tight lot.

Can HOAs deny ADUs in California if AB 956 take effect in 2027?

AB 956 would update section 714.3 of the Civil Code to specify that HOAs and planned developments cannot prohibit or unreasonably restrict the construction of an ADU on a lot zoned to allow single-family residential use. In the past, hazy language led to cases like Mystic Point Homeowners Association v. Hardesty where ultimately, the presiding judge ruled in favor of the HOA and blocked the garage conversion ADU. With these minor updates to the law, California disarms owner associations from blocking the state’s instituted pathways to build more homes and address the housing shortage.

If you want to understand the development potential for your site, OpenScope specializes in smart urban infill solutions backed by a thorough understanding of policy and years of experience applying it. We can help develop fit plans for your property and explain your options. Through our network we can also connect you with skilled land use attorneys, contractors and other professional consultants to help bring your project to reality.

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FAQs

Not anymore, as long as the unit has its own dedicated bathroom.

Not yet. AB 956 has passed the state Senate and Assembly, but is currently awaiting Governor Newsom’s signature. If signed, it will take effect January 1, 2027. Until then, current ADU law applies: one detached ADU, one conversion ADU and one JADU per single-family parcel under CA Gov code 66323.

Not under AB 956. The bill amends Civil Code 714.3 so that no covenant, condition or restriction can prohibit or unreasonably restrict a legal ADU on a lot zoned to allow single-family residential use.

Not automatically. Subdivision (b) says a local agency is not required to ministerially approve a JADU on a lot where two detached new-construction ADUs have already been built. The bill does not state the reverse – adding two detached ADUs on a lot with an existing JADU is not specifically excluded. But keep in mind this reading has not been vetted, it is a sequencing strategy based on the bill’s text, not a guarantee.

At most single-family parcels, owners can typically assume at least 3 ADUs can be added: 2 detached ADUs and 1 conversion ADU under AB956’s amendments to state law. An additional JADU can be built, only if it is proposed before the 2 detached ADUs (subject to local interpretation or future interpretation from HCD)

If a local ADU program is in place, an extra unit can be added, bringing the site total to 5.

Build the local ordinance “66314” ADU first if your jurisdiction has a program in place. “66314” ADUs typically take up more space on site due to objective standards for setbacks, yards and FAR.

Then, see if any of the “66323” ADUs can fit: 1 conversion ADU, 1 JADU and 1 detached ADU. These units are exempt from local regulations but must comply with state height limits and 4’ setbacks.

If AB 956 goes into effect, the number of allowable detached ADUs increases from 1 to 2. But to include all 4 of the state exempt ADUs under AB 956, the JADU must be proposed before the detached ADUs.

AB 956 addresses single-family parcels. At multifamily properties, up to 8 detached ADUs can be built (not to exceed the total of existing units), and the number of proposed conversion ADUs is limited to 25% of the existing unit count.