Accessory dwelling units and junior accessory dwelling units.

Enrolled bill header (Senate/Assembly passage dates, Governor receipt date, secretary signatures) replaced with chaptered bill header showing Chapter 520, approval date of October 10, 2025, and 'AUTHENTICATED ELECTRONIC LEGAL MATERIAL' designation.

Page headers changed from 'SB 543' to 'Ch. 520' throughout the document, and line wrapping was reformatted to match the official chaptered layout.

Removed amendment history lines (dates of prior amendments) and replaced with passage dates: Passed the Senate September 2, 2025 and Passed the Assembly August 28, 2025.

Added Governor's receipt line indicating the bill was received by the Governor on a blank date in 2025, which is standard for enrolled bills awaiting signature.

Removed line-by-line numbering (e.g., 'line 1', 'line 2') that was present in the amended version, consistent with standard enrolled bill formatting.

In Section 66323(a), removed a duplicated word 'following' that appeared as a drafting error ('the following: following units' corrected to 'the following units').

The diff replaces the official chaptered bill format (with 'STATE OF CALIFORNIA AUTHENTICATED ELECTRONIC LEGISLATURE MATERIAL' header, page numbers, and formal section layout) with a web page rendering that includes navigation menus, search fields, sidebar links, and website metadata. The underlying legislative text is identical.

The impact fee exemption threshold for JADUs was lowered from 750 square feet to 500 square feet of interior livable space. Previously, JADUs up to 750 sq ft were exempt from impact fees; now only those up to 500 sq ft are exempt. The proportional impact fee requirement for larger units was also clarified to apply only to ADUs (not JADUs) exceeding 750 sq ft.

New provisions on utility connections: for one ADU plus one JADU per lot with a single-family dwelling, no new or separate utility connection may be required (and no related fee charged) unless the unit was built with a new single-family dwelling or is separately conveyed. For other ADUs, connections may be required but fees must be proportionate to the unit's square footage or drainage fixture unit values.

Clarification that an ADU or JADU with less than 500 square feet of interior livable space does not increase assessable space by 500 square feet for purposes of school district construction fees under Education Code Section 17620.

A new appeal process was added: if a permit application is determined incomplete or denied, the permitting agency must provide a written appeal process to the governing body or planning commission, and must issue a final written determination within 60 business days of receiving the appeal.

New enforcement mechanism for JADU ordinances: local agencies must submit their JADU ordinance to the Department of Housing and Community Development within 60 days of adoption. If the department finds the ordinance noncompliant and the agency fails to submit or respond, the ordinance is nullified and void.

Explicit prohibition added that no local ordinance, policy, or regulation (other than a compliant ADU or JADU ordinance) may be used as the basis for delaying or denying a building permit or use permit under the ministerial approval provision. This was added for both ADUs and JADUs.

Section 66320 was simplified to remove redundant 60-day timeline and deemed-approval language, instead simply referencing Section 66317 for the ministerial review process. The detailed approval timelines remain in Section 66317.

Senator Arreguin was added as a co-author of the bill in the Assembly amendment.

JADUs were removed from the 60-day ministerial approval requirement in Section 66317. Previously, both ADU and JADU permit applications had to be approved or denied within 60 days (with deemed approval if no action was taken). Now only ADU applications are subject to this timeline under that section.

JADUs were similarly removed from the ministerial approval provisions in Section 66320, which governs permit processing when a local agency has not adopted an ADU ordinance. The 60-day deemed-approval clock now applies only to ADU applications under that section.

The fiscal committee designation changed from 'no' to 'yes,' meaning the bill now requires a fiscal impact analysis by the Legislative Analyst's Office, indicating the amendment introduces new state or local costs that were not present in the prior version.

The state-mandated local program designation changed from 'no' to 'yes,' formally acknowledging that the bill imposes duties on local agencies that qualify as a state-mandated local program under the California Constitution, which can trigger reimbursement obligations.

A provision making nonsubstantive changes to public notice and hearing requirements for development projects was removed from the bill entirely, along with its corresponding digest language.

The bill's scope expanded from amending only Section 65956 (public notice provisions) to amending and adding provisions across Sections 65941.1, 66311, 66313, 66317, 66320, 66321, 66323, 66335, 66324 (renumbered to 66311.5), 66327 (renumbered to 66313.5), and 66332 (renumbered to 66311.7), plus adding new Sections 66333.5, 66335.5, and 66339.5.

The Department of Housing and Community Development's authority to adopt guidelines implementing uniform standards was expanded to cover JADUs in addition to ADUs. The legislative intent declaration regarding ADU ordinances now also applies to JADU ordinances.

The definition of 'junior accessory dwelling unit' was changed from 'no more than 500 square feet in size' to 'no more than 500 square feet of interior livable space,' which allows a larger physical footprint since interior livable space excludes walls and non-habitable areas.

The 90-day period for a development proponent to submit missing information after an agency determines a housing development application is incomplete now resets each time the proponent resubmits information, and the agency and proponent may mutually agree to extend the period. Previously the clock ran continuously.

Maximum size limitations for ADUs were revised to be based on interior livable space. The maximum for a standard ADU was increased from 800 to 850 square feet of interior livable space, and the multi-bedroom threshold is now 1,000 square feet of interior livable space. Local agencies must permit at least an 800-square-foot ADU (interior livable space) with four-foot side and rear setbacks.

Specific height limitations were added: 16 feet for detached ADUs on single-family lots, 18 feet near major transit stops or high-quality corridors, 18 feet on multifamily lots, and 25 feet (or the primary dwelling's height limit, whichever is lower) for attached ADUs, plus an additional two feet for roof pitch alignment.

The prohibition on requiring fire sprinkler installation in an ADU when the primary residence does not require sprinklers was extended to also apply to JADUs.

Local agencies must submit JADU ordinances to the Department of Housing and Community Development within 60 days after adoption for review, and JADU standards supersede conflicting local ordinances, mirroring existing requirements for ADU ordinances.

Local agencies that have not adopted a JADU ordinance must now consider JADU permit applications ministerially within 60 days, mirroring the existing requirement for ADUs. Applications for ADUs or JADUs are deemed complete in the same form and manner as postentitlement permits.

The bill now allows combinations of ADUs and JADUs: one ADU and one JADU per lot with a single-family dwelling (where the JADU is within existing space), or a detached new-construction ADU combined with a JADU. Previously these were treated separately.

The impact fee prohibition now applies to both ADUs and JADUs with 750 square feet or less of interior livable space (previously only ADUs at 750 square feet). Impact fees on larger units must be charged proportionately. School district fees: an ADU or JADU with less than 500 square feet of interior livable space does not increase assessable space by 500 square feet.

The bill now imposes a state-mandated local program (changed from 'no' to 'yes'), which triggers California Constitution requirements for state reimbursement of costs imposed on local agencies. The fiscal committee determination also changed from 'no' to 'yes.'

The entire preliminary application process for housing development projects (Section 65941.1) was deleted. This removed the deemed-submission trigger, the 180-day deadline to file a full application, the 90-day cure period with reset and mutual extension provisions, fee and exaction estimate requirements, and the January 1, 2030 sunset date.

The ministerial approval provision (no discretionary review or hearing) now explicitly applies to JADU permit applications in local agencies that have not adopted a JADU ordinance, extending a protection that previously applied only to ADUs in jurisdictions without an ADU ordinance.

The impact fee exemption threshold for JADUs was lowered from 750 square feet to 500 square feet of interior livable space. ADUs retain the 750 square foot threshold. This means JADUs above 500 square feet (which is their maximum allowed size) can now be subject to impact fees, while ADUs up to 750 square feet remain exempt.

A new requirement was added that permitting agencies must determine whether an ADU or JADU application is complete within 15 business days of receipt and provide written notice. If incomplete, the agency must list all deficient items and explain how to cure them. The agency may not require additional items beyond those listed. If the agency fails to make a timely determination, the application is deemed complete.