Public Law Update – 2025 ADU Legislative Update

The California legislature enacted four new bills making further changes to Accessory Dwelling Unit (“ADU”) and Junior Accessory Dwelling Unit (“JADU”) laws.  Local agencies should understand how these new laws change how ADUs and JADUs are processed and update their local implementation ordinances accordingly. Specifically, the following bills have been enacted and, except where noted below, will take effect January 1, 2026:

• Senate Bill 543 (2025) (“SB 543”)
• Senate Bill 9 (2025) (“SB 9”)
• Assembly Bill 462 (2025) (“AB 462”)
• Assembly Bill 1154 (2025) (“SB 1154”)

Below is a summary of the significant changes made by these bills.

Legislative Intent was modified to expressly state that local ordinances governing ADUs and JADUs cannot unreasonably restrict the ability to create ADUs and JADUs. (SB 543).

Maximum size for ADUs and JADUs was clarified by providing that all sizes discussed in the Government Code are net square footage. The phrase “interior livable space” was added to various sections governing minimum and maximum square footages. (SB 543).

Ministerial approval now requires that local agencies adhere to the post-entitlement shot clocks in processing ADUs and JADUs. SB 543 amends Government Code sections 66317 and 66335 by requiring that ADU and JADU applications be reviewed for completeness within 15 business days, and local agencies must provide an appeal process and reach a determination within 60 days of receipt of a written appeal. (SB 543).

Furthermore, SB 543 requires that all jurisdictions, including those that do not adopt a local ordinance, comply with the ministerial process described above and removed the ability to delay approval of ADUs and JADUs until the primary single family or multifamily dwelling is built. (SB 543).

Statutory ADU provisions pursuant to Government Code section 66323 were modified to codify HCD’s guidance regarding the number of ADUs that must be permitted per lot.  The amendments specify that local agencies must allow both one attached and one detached ADU, plus one JADU, on a single family lot, internal and external ADUs on multifamily lots, and fire sprinklers may not be required for JADUs if they are not required for the primary dwelling. (SB 543).

Occupancy requirements for JADUs now prohibit local agencies, including cities and counties, from imposing owner occupancy requirements when a JADU has independent sanitation facilities. (SB 9). Additionally, local agencies must require that JADUs be rented for terms longer than 30 days. (AB 1154).

Certificates of occupancy cannot be issued to ADUs before a certificate of occupancy is issued for the primary dwelling, under existing law. AB 462 requires that a certificate of occupancy be issued for an ADU when constructed in a county that is the subject of a proclamation of emergency made by the governor after Feb. 1, 2025, the primary dwelling is destroyed by the event described in the emergency proclamation, and the ADU is issued construction permits and passes all inspections. These amendments took effect immediately on Oct. 10, 2025.

Coastal permit applications to create an ADU must be approved or denied within 60 days of the local agency/ coastal commission receiving a complete application. (AB 462). AB 462 requires that the coastal development permit process occur concurrently with the planning/ zoning permit application and failure to act within 60 days results in the application being deemed approved.

Fee limitations previously imposed on ADUs now also apply to JADUs. Additionally, ADUs and JADUs that are less than or equal to 500 square feet of interior livable space are exempt from school fees. (SB 543). These amendments took effect immediately on Oct. 10, 2025.

Review by the California Department of Housing and Community Development (“HCD”) review is now required for all JADU ordinances. Previously, this was required for ADU ordinances only. (SB 543).

Additionally, local agency ADU ordinances adopted pursuant to Government Code section 66314 are null and void if not timely submitted to HCD, including timely responding to HCD’s findings that a local ordinance does not comply with California law, and adoption of a non-compliant ordinance may be referred to the Attorney General for enforcement. (SB 9).

Burke, Williams & Sorensen, LLP regularly advises clients on legal matters relating to land use, zoning, and planning issues.

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