To: Board of Supervisors
From: John Kopchik, Director, Conservation and Development
Report Title: 2025 California Building Code Adoption
☒Recommendation of the County Administrator ☐ Recommendation of Board Committee
RECOMMENDATIONS:
CONSIDER accepting a report on adoption of the 2025 California Building Code, as presented to the Sustainability Committee and provide direction to staff.
FISCAL IMPACT:
None
BACKGROUND:
Triennial Building Code Cycle and Adoption of the 2025 California Building Code
Since 2007, the State of California has adopted a new statewide building code every three years, known as the California Building Standards Code (CBSC). The California Building Standards Commission has now adopted and released the 2025 CBSC, replacing the 2022 CBSC. The 2025 CBSC includes the California Building, Residential, Electrical, Mechanical, Plumbing, Energy, Wildland-Urban Interface, Historical Building, Existing Building and Green Building Standards Codes. These statewide codes will become effective January 1, 2026. The Department of Conservation and Development is responsible for enforcing the CBSC within the unincorporated area of Contra Costa County.
Local agencies are not required to adopt the California Building Code, but must do so by adopting an ordinance if they propose to amend the statewide code (if not amended, the statewide code becomes effective without any action required by the local jurisdiction). Cities and counties have the authority to adopt amendments to the statewide code if such amendments are more restrictive than statewide code requirements and amendments must be accompanied by findings that the changes and modifications to the statewide code are reasonably necessary because of local climatic, topographical, geological or environmental conditions. Local amendments to the California Energy Code must also be approved by the California Energy Commission and must be accompanied by a finding that such amendments are cost effective.
Contra Costa County has a history of adopting a limited number of amendments to the CBSC in past code cycles. Some of the County’s local amendments were established decades ago and address health and safety concerns related to local conditions such as seismic risks and unstable soils that occur throughout the County.
In more recent years, the Board of Supervisors has also adopted local building code amendments addressing concerns related to climate change. These include increasing requirements for the installation of electric vehicle chargers and increasing energy efficiency standards for new residential and non-residential buildings.
Recent Changes to State Law concerning Local Amendments to the State Building Code
Recent changes to State law have placed new additional restrictions on the authority of local jurisdictions to amend the CBSC as it relates to the construction of new residential housing units. State budget legislation adopted at the end of June, AB 130, includes changes to the Health and Safety Code that limit the authority of local jurisdictions to adopt building code amendments related to the construction of new housing to those amendments already in effect as of September 30, 2025, with a few narrowly defined exceptions. These changes to local authority will remain in effect from October 1, 2025, until June 1, 2031. This means the County can continue its current code amendments into the new code cycle but is restricted in its authority to adopt new code amendments related to residential construction in the 2025 CBSC. Local jurisdictions retain broader discretion to adopt code amendments related to non-residential construction, subject to making the required findings.
Development of 2025 Building Code Adoption Ordinance
Staff in the Department of Conservation and Development, working closely with County Counsel, are currently drafting an ordinance for the Board of Supervisors to consider that would adopt the 2025 CBSC with local amendments. This process involves reviewing the new statewide code and determining which existing local code amendments should be eliminated or modified based on changes to the statewide code and which are still needed in their current form. In some areas, changes to the statewide code have made the State building code more restrictive, resulting in some of the County’s existing local amendments no longer being necessary.
Staff are giving special attention to two areas of the 2025 CSBC that have been amended by the Board of Supervisors in recent code cycles: electric vehicle charging and the energy efficiency requirements in the energy code. These two areas are discussed in more detail below.
Electric Vehicle Charging
In the last code cycle, the Board of Supervisors amended the 2022 CBSC to increase the requirements for electric vehicle chargers for new multifamily residential and new non-residential construction. The current local amendments now in effect require 10% of parking spaces in both new multifamily residential and new non-residential developments to have an electric vehicle charger installed.
While statewide code requirements for electric vehicle charging have increased somewhat in the new code, the County’s existing local amendment for multifamily developments remains necessary to ensure that all new multifamily developments are required to have at least 10% of parking spaces served by an electric vehicle charger under the 2025 CBSC. Therefore, staff recommend this local amendment be retained as part of the Board’s adoption of the 2025 CBSC.
Similarly, the County’s existing local amendment for new non-residential construction continues to be necessary to ensure all such developments are required to have at least 10% of parking spaces served by an electric vehicle charger under the 2025 CBSC. However, the requirements in the 2025 CBSC now exceed the requirements of the County’s current local code amendment for office and retail developments specifically. The 2025 CBSC will require all new office and retail developments to have up to 15% of all parking spaces served by electric vehicle chargers. Staff recommend the Board retain those portions of the current local amendment that exceed state requirements to ensure at least 10% of parking spaces are equipped with an electric vehicle charger for all new non-residential developments.
Energy Efficiency Requirements for New Buildings
The current local amendments to the California Energy Code adopted by the Board of Supervisors in 2024 increase the energy efficiency requirements for new residential and non-residential buildings above the minimum requirements of the 2022 CBSC, which remains in effect until the end of 2025. However, the requirements in the new 2025 California Energy Code, which will become effective January 1, 2026, exceed the requirement of the County’s current local code amendments. Therefore, the County’s existing local amendments will no longer be needed under the new code and staff recommend these amendments be removed from the County’s code adoption ordinance.
As described above, State law now restricts the County’s authority to adopt new building code amendments that impact residential construction. The Board of Supervisors retains broader authority to consider new amendments impacting non-residential construction. However, any new Energy Code amendments would require approval from the California Energy Commission and would need to be supported by a finding that the requirements imposed by the local amendments are cost effective. Currently, no cost effectiveness studies exist that would support such a finding.
In past code cycles, the California Public Utilities Commission funded cost effectiveness studies of energy code amendments to assist local jurisdictions to determine if such amendments were cost effective, but such studies are not yet available for the 2025 code. Therefore, staff cannot recommend any amendments to the 2025 California Energy Code at this time. Local amendments to the California Energy Code could be considered in the future once cost effectiveness data becomes available. Staff recommend the Board direct staff to monitor this issue and report back to the Sustainability Committee in 2026.
CONSEQUENCE OF NEGATIVE ACTION:
If the Board does not receive the report, staff will not receive direction needed to prepare a building code adoption ordinance to implement the 2025 California Building Code with local amendments.