ADU Law Summary
Updated: Feb 4
(Updated 2-1-26)
These are the major new ADU laws for 2026. The links are to the California Legislation Information page, which is an excellent source for the actual legislation. Here is a link to the Bill Search main page. Just enter the Bill title, i.e., AB XX or SB XX, to see a great summary of each bill. California Legislative Information home page
Provides that owner occupancy of a primary dwelling is not required if the JADU has separate sanitation facilities.
Requires that a JADU be rented for a term longer than 30 days, meaning JADUs cannot be used for short-term rentals (e.g., Airbnb rentals).
Provides additional clarification on the unit entrance and kitchen.
Clarifies that ADU floor area is measured as “interior livable space,” meaning that exterior wall thickness and attic areas with low ceilings are not included in the ADU area.
Shortens the maximum evaluation period for the completeness of an ADU application to 15 business days.
Requires local agencies to approve ADU applications within 60 days (or deem them approved) and to provide clear reasons for denial.
Generally, prohibits construction, connection, impact fees, and capacity charges for ADUs under 750 sf.
Amends fire sprinkler requirements for JADUs to align with those for ADUs.
SB 1211 Expanded the number of detached ADUs for multifamily properties to up to eight units, with 1 ADU per multifamily unit.
AB 2533 Provided a path to legalizing previously unpermitted ADUs without significant penalties.
The following new laws for 2026 affect California housing in general and now specifically include ADUs. Go to each bill to see how it affects the new California ADU law.
SB 450 It primarily targets ministerial approval for duplexes and urban lot splits, and it directly impacts the ability to add accessory dwelling units (ADUs) on those lots by streamlining the overall development process and curbing local restrictions.
Important California bills affecting housing and ADUs from previous years
SB 1123 ADU Exemption from Unit Cap: If a local agency permits an accessory dwelling unit (ADU) or a junior accessory dwelling unit (JADU) on a parcel created under this Act, those units do not count toward the development's 10-unit maximum. While SB 1123 streamlines the subdivision of main lots, it does not require cities to allow ADUs on these new, smaller subdivided lots; it only states that, if permitted, such units do not count against the 10-unit cap.
AB 2580 Signed into law in September 2024, California's AB 2580 (Wicks) enhances transparency for local historic designations to prevent their misuse in delaying housing projects, including Accessory Dwelling Units (ADUs).
SB 937 Applies to designated residential development projects, including housing projects with 10 or fewer units. It specifically benefits the construction of ADUs over 750 square feet, which are often subject to higher impact fees.
Expanded "Major Transit Stop" Definition: The bill redefines a major transit stop to include the intersection of two or more bus routes operating at a frequency of 20 minutes or less (previously 15 minutes).
Parking & Development Benefits: By redefining transit proximity, more ADUs and junior ADUs (JADUs) on properties near these now-qualified stops may qualify for reduced or eliminated parking requirements.
Lower Traffic Impact Fees: The bill requires local agencies to charge lower traffic impact fees for housing developments (including ADUs) located within a half mile of a major transit stop.
Transit Proximity Benefits: The updated definition expands access to state-level, transit-oriented benefits, such as increased height allowances for detached ADUs, to more properties.
Enforcement of ADU Rules: If the California Department of Housing and Community Development (HCD) finds that a city's housing policies (including its ADU ordinances) are noncompliant, those local actions are now legally presumed invalid in court.
Reduced Rezoning Deadlines: Local governments that miss housing element milestones will have only one year (instead of three) to complete the required rezonings to meet their housing goals, often including increased ADU capacity.
AB 2729 Specifically extends the expiration date for local, ministerial, and administrative approvals or permits for residential development projects by 18 months. It includes building permits, which can cover ADU projects that were previously approved but delayed.
AB 1893 Projects of 10 units or fewer, including developments with multiple ADUs or small duplex/townhome projects, are exempt from the strict affordability requirements. The bill enables more residential units, including ADUs, by allowing 50% mixed-use projects (down from 66% in some cases) to qualify as housing developments, thereby fostering denser infill development.
SB 1037 Serves as an enforcement mechanism for existing "by-right" or ministerial approval laws (such as SB 9 and general ADU laws) that prevent local governments from denying or unduly delaying ADU projects that meet objective standards.