SB 543: Accessory dwelling units and junior accessory dwelling units.

Official summary

Legislative Counsel’s Digest (official, as of the latest version). Written by nonpartisan legislative staff; reproduced verbatim.

Existing law, the Planning and Zoning Law, among other things, provides for the creation by ordinance, or by ministerial approval if the local agency has not adopted an ordinance, of an accessory dwelling unit (ADU) or a junior accessory dwelling unit (JADU) in accordance with specified standards and conditions. Existing law defines the term “junior accessory dwelling unit” for these purposes to mean a unit that is no more than 500 square feet in size and contained entirely within a single-family structure.

This bill would revise the definition of a “junior accessory dwelling unit” to require the size of a JADU to be no more than 500 square feet of interior livable space.

Existing law makes certain declarations of the Legislature’s intent regarding the effect of an ADU ordinance. Existing law authorizes the Department of Housing and Community Development to review, adopt, amend, or repeal guidelines to implement uniform standards or criteria that supplement or clarify the terms, references, and standards for an ADU.

This bill would revise the above-described declaration of legislative intent to additionally apply with respect to a JADU ordinance. The bill would also expand the department’s authority to review, adopt, amend, or repeal guidelines to additionally grant that authority with respect to terms, references, and standards for JADUs.

Existing law requires a local agency to submit an ADU ordinance to the Department of Housing and Community Development within 60 days after the adoption for department review, as specified. Under existing law, the standards applicable to an ADU under these provisions supersede a conflicting local ordinance, except as specified.

This bill would similarly require a local agency to submit a JADU ordinance to the department within 60 days after adoption for department review and would require the department to notify the local agency if the ordinance is noncompliant with JADU ordinance requirements, as specified. The bill would nullify and void that ordinance if the local agency fails to submit a copy of that ordinance or respond to the department’s findings that the ordinance is noncompliant, as specified. The bill would also specify that the standards applicable to a JADU supersede any conflicting local ordinance, except as specified.

Sponsors

Sponsors by party (alphabetical): Democratic 2

“Support” is shown only as formal sponsorship recorded by the legislature. Roll-call votes are available on the official bill page.

Recent official actions

1. October 10, 2025Chaptered by Secretary of State. Chapter 520, Statutes of 2025.
2. October 10, 2025Approved by the Governor.
3. September 9, 2025Enrolled and presented to the Governor at 2 p.m.
4. September 2, 2025Assembly amendments concurred in. (Ayes 40. Noes 0. Page 2408.) Ordered to engrossing and enrolling.
5. August 28, 2025In Senate. Concurrence in Assembly amendments pending.
6. August 28, 2025Read third time. Passed. (Ayes 75. Noes 0. Page 2773.) Ordered to the Senate.
7. August 21, 2025Read second time. Ordered to third reading.
8. August 20, 2025From committee: Do pass. (Ayes 15. Noes 0.) (August 20).
9. July 17, 2025From committee: Do pass and re-refer to Com. on APPR. (Ayes 10. Noes 0.) (July 16). Re-referred to Com. on APPR.
10. July 8, 2025From committee with author's amendments. Read second time and amended. Re-referred to Com. on L. GOV.
11. June 19, 2025Read second time and amended. Re-referred to Com. on L. GOV.
12. June 18, 2025From committee: Do pass as amended and re-refer to Com. on L. GOV. (Ayes 11. Noes 0.) (June 18).