Cal. Health & Safety Code § 17958

(a) Except as provided in subdivision (b), and in Sections 17958.8 and 17958.9, any city or county may make changes in the provisions adopted pursuant to Section 17922 and published in the California Building Standards Code or the other regulations thereafter adopted pursuant to Section 17922 to amend, add, or repeal ordinances or regulations which impose the same requirements as are contained in the provisions adopted pursuant to Section 17922 and published in the California Building Standards Code or the other regulations adopted pursuant to Section 17922 or make changes or modifications in those requirements upon express findings pursuant to Sections 17958.5 and 17958.7. If any city or county does not amend, add, or repeal ordinances or regulations to impose those requirements or make changes or modifications in those requirements upon express findings, the provisions published in the California Building Standards Code or the other regulations promulgated pursuant to Section 17922 shall be applicable to it and shall become effective 180 days after publication by the California Building Standards Commission. Amendments, additions, and deletions to the California Building Standards Code adopted by a city or county pursuant to Section 17958.7, together with all applicable portions of the California Building Standards Code, shall become effective 180 days after publication of the California Building Standards Code by the California Building Standards Commission.
(b) Commencing October 1, 2025, to June 1, 2031, inclusive, a city or county shall not make changes that are applicable to residential units in the provisions adopted pursuant to Section 17922 and published in the California Building Standards Code or the other regulations thereafter adopted pursuant to Section 17922 to amend, add, or repeal ordinances or regulations which impose the same requirements as are contained in the provisions adopted pursuant to Section 17922 and published in the California Building Standards Code or the other regulations adopted pursuant to Section 17922 or make changes or modifications in those requirements upon express findings pursuant to Sections 17958.5 and 17958.7, unless one of the following conditions is met:
1. (1) The changes or modifications are substantially equivalent to changes or modifications that were previously filed by the governing body of the city or county and were in effect as of September 30, 2025.
2. (2) The commission deems those changes or modifications necessary as emergency standards to protect health and safety.
3. (3) The changes or modifications relate to home hardening.
4. (4) The building standards relate to home hardening and are proposed for adoption by a fire protection district pursuant to Section 13869.7.
5. (5) The changes or modifications are necessary to implement a local code amendment that is adopted to align with a general plan approved on or before June 10, 2025, and that permits mixed-fuel residential construction consistent with federal law while also incentivizing all-electric construction as part of an adopted greenhouse gas emissions reduction strategy.
6. (6) The changes or modifications are related to administrative practices, are proposed for adoption during the intervening period pursuant to Section 18942, and exclusively result in any of the following:
  1. (A) Reductions in time for a local agency to issue a postentitlement permit.
  2. (B) Alterations to a local agency’s postentitlement fee schedule.
  3. (C) Modernization of, or adoption of, new permitting platforms and software utilized by the local agency.
  4. (D) Reductions in cost of internal operation for a local agency.
  5. (E) Establishment, alteration, or removal of local programs related to enforcement of building code violations or complaints alleging building code violations.