(1) Existing law establishes the Department of Housing and Community Development (department) in the Business, Consumer Services, and Housing Agency. Existing law, the California Building Standards Law, establishes the California Building Standards Commission (commission) within the Department of General Services. Existing law requires the commission to approve and adopt building standards and to codify those standards in the California Building Standards Code (code) . Existing law, the State Housing Law, establishes statewide construction and occupancy standards for buildings used for human habitation.
Existing law requires, among other things, the building standards adopted and submitted by the department for approval by the commission, as specified, to be adopted by reference, with certain exceptions. Existing law authorizes any city or county to make changes in those building standards that are published in the code, including to green building standards. Existing law requires the governing body of a city or county, before making modifications or changes to those green building standards, to make an express finding that those modifications or changes are reasonably necessary because of local climatic, geological, or topographical conditions.
This bill would, from June 1, 2025, to June 1, 2031, inclusive, prohibit a city or county from making changes that are applicable to residential units to the above-described building standards unless a certain condition is met, including that the commission deems those changes or modifications necessary as emergency standards to protect health and safety.
This bill would, from June 1, 2025, to June 1, 2031, inclusive, require the commission to reject a modification or change to any building standard, as described above, affecting a residential unit and filed by the governing body of a city or county unless a certain condition is met, including that the commission deems those changes or modifications necessary as emergency standards to protect health and safety. The bill would also make related findings and declarations.
(2) The California Building Standards Law defines various terms to govern the construction of its provisions, including "model code," which means any building code drafted by private organizations or otherwise, and is required to include, but not be limited to, the latest edition of various codes.
This bill would modify the definition of "model code" to add the latest edition of the International Wildland-Urban Interface Code of the International Code Council.
(3) Existing law requires the commission to receive proposed building standards from state agencies for consideration in an 18-month code adoption cycle and to develop regulations, as specified, setting forth the procedures for the 18-month adoption cycle.
This bill, from June 1, 2025, to June 1, 2031, inclusive, would provide that the above-described requirement does not apply to any building standards affecting residential units and would prohibit the commission from considering, approving, or adopting any proposed building standards affecting residential units, unless a certain condition is met, including that the commission deems those changes necessary as emergency standards to protect health and safety.
(4) The California Building Standards Law provides for the adoption of building standards by state agencies by requiring all state agencies that adopt or propose adoption of any building standard to submit the building standard to the commission for approval and adoption.
This bill, from June 1, 2025, to June 1, 2031, inclusive, would prohibit the commission or any other adopting agency from considering, approving, or adopting any proposed building standards affecting residential units, unless a certain condition is met, including that the commission deems those changes necessary as emergency standards to protect health and safety.
(5) Existing law requires only those building standards approved by the commission, and that are effective at the local level at the time an application for a building permit is submitted, to apply to the plans and specifications for, and to the construction performed under, that building permit. Existing law requires a local ordinance adding or modifying building standards for residential occupancies, which are published in the California Building Standards Code, to apply only to an application for a building permit submitted after the effective date of the ordinance and to the plans and specifications for, and the construction performed under, that permit, subject to certain exceptions.
This bill would, notwithstanding those provisions, require the state and local building standards in effect at the time an application for a building permit is submitted, for a residential dwelling based on a model home design approved under those standards, to apply to all future residential dwellings based on that approved model home design, unless a certain condition applies. By requiring local entities to apply certain building standards, this bill would impose a state-mandated local program.
(6) Existing law provides that neither the State Building Standards Law, nor the application of certain building standards, limits the authority of a city, county, or city and county to establish more restrictive building standards, including, but not limited to, green building standards, reasonably necessary because of local climatic, geological, or topographical conditions, and pursuant to making certain findings.
This bill would, notwithstanding those provisions, from June 1, 2025, to June 1, 2031, inclusive, prohibit a city or county from establishing more restrictive building standards that are applicable to residential units, unless a certain condition is met, including that the commission deems those changes or modifications necessary as emergency standards to protect health and safety.
(7) Existing law requires the commission to publish, or cause to be published, editions of the code in its entirety once in every 3 years, and supplements as necessary in the intervening period. Existing law also requires an emergency building standards supplement to be published whenever the commission determines it is necessary.
This bill would limit the changes adopted during the intervening period to changes deemed necessary for editorial or clarity reasons, emergency building standards, amendments by the State Fire Marshal to specified building standards, and certain necessary building standards and related state amendments.
(8) The bill would include findings that changes proposed by this bill address a matter of statewide concern rather than a municipal affair and, therefore, apply to all cities, including charter cities.
(9) The California Constitution requires the state to reimburse local agencies and school districts for certain costs mandated by the state. Statutory provisions establish procedures for making that reimbursement.
This bill would provide that no reimbursement is required by this act for a specified reason.
(10) This bill would declare that it is to take effect immediately as an urgency statute.

Statutes affected:
AB 306: 17958 HSC, 17958.5 HSC, 17958.7 HSC, 18929.1 HSC, 18930 HSC
01/23/25 - Introduced: 17958 HSC, 17958.5 HSC, 17958.7 HSC, 18929.1 HSC, 18930 HSC
03/05/25 - Amended Assembly: 17958 HSC, 17958.5 HSC, 17958.7 HSC, 18929.1 HSC, 18930 HSC
03/12/25 - Amended Assembly: 17958 HSC, 17958.5 HSC, 17958.7 HSC, 18929.1 HSC, 18930 HSC
05/13/25 - Amended Senate: 17958 HSC, 17958.5 HSC, 17958.7 HSC, 18916 HSC, 18916 HSC, 18929.1 HSC, 18930 HSC, 18938.5 HSC, 18938.5 HSC, 18941.5 HSC, 18941.5 HSC, 18942 HSC, 18942 HSC