2025 Triennial
Code Adoption
Michael Titsworth - Deputy Director / Building Official Mary Eusebio - Deputy Building Official
Community Development Department
2025 Triennial Building Code Update
RECOMMEMDATION:
• Amendment of various sections of the San Mateo Municipal Code Title 23 Buildings and Construction, including those to reflect the 2025 California Building Standards Code. • Amend with clerical updates to Chapters 23.44 EV Charging Stations and 23.46 Small Residential Rooftop Solar Energy Systems.
• Adopt the new Wildland-Urban Interface (WUI) Code, which addresses the growing risk of wildfire in areas where urban development meets or intermingles with wildland vegetation. • Adopt a Resolution with express findings supporting local amendments to the 2025 California Building Standards Code
ASSEMBLY BILL 130 COMPLIANCE
• AB 306 (prior bill): Attempted to freeze residential building codes for extended periods, effectively limiting the ability of jurisdictions to apply updated safety standards at the local level. • AB 130 (current law): Approved by the Governor June 30, 2025, as part of a budget trailer bill package.
Amendments are tied to the specific allowances under H&S §17958.5 and §17958.7, which permit local changes to the California Building Standards Code commencing October 1, 2025, to June 1, 2031, only if the local changes are:
1. Substantially equivalent to prior approved local modifications;
2. Necessary as emergency standards to protect public health and safety;
3. Related to wildfire/home hardening measures;
4. Related to adoptions by the local fire prevention district;
5. Changes or modifications necessary to implement and align with approved General Plan; or
6. Related to administrative practices for efficiency, cost reduction, or modernization of processes. • Key distinction: AB 130 strikes a balance between predictability for developers and local flexibility to address critical health, safety, and wildfire risks—whereas AB 306 largely blocked local adaptation of residential codes.
• Local amendments proposed for 2025 are narrow in scope, focusing on seismic safety, fire protection, and energy resilience, consistent with the state’s intent.
2025 Triennial Building Code Update:
• The California Building Standards Code (CBSC or State Code) is published in its entirety every three years, with supplements published in intervening years. • Specific Codes: Administrative, Building, Residential, Electrical, Mechanical, Plumbing, Energy, (New) Wildland-Urban Interface, Historical, Fire, Existing Building, Green Building, and Reference Standards Codes. • Effective Date: January 1, 2026.
• The last local and Triennial State Code Update was in 2022 and took effect on January 1, 2023.
• REACH CODES: This update under consideration, does not contain local amendments to the model Energy and Green Building Codes. City Council will review REACH Codes in a separate report at a future date.
Municipal Code
Title 23 BUILDING & CONSTRUCTION
This code adoption proposal is like most code adoption years adopting the most current version of the 2025 Model State Codes with local amendments. • Update the municipal code to align with the new state code for the next three- year code cycle.
• Correct improper references to the model codes.
• Add local amendments known as Code Appendices, to increase public safety, streamline and expedite some processes, and align requirements in Residential and Building Codes.
• Adopt the new Wildland-Urban Interface (WUI) Code as Chapter 23.29, which addresses the growing risk of wildfire in areas where urban development meets or intermingles with wildland vegetation.
23.07 RESIDENTIAL CODE
Amendments
Chapter R602
• Provides greater seismic design for wall bracing materials.
Appendix BF – Patio Covers:
• Streamlines and expedites processing of recreational project permits not exceeding 12’ in height.
Appendix BG - Sound Transmissions:
• Increases the well-being of building occupants by mitigating the sound transmission from other spaces and between dwelling units.
Appendix CI - Swimming Pool Safety Act:
• Enhanced safety measures for swimming pools and spas in residential settings.
23.08 BUILDING CODE
Amendments
Chapters 15, 17, 23, and 31:
• 1505 - Greater fire resistance of roof coverings in all construction types. • 1705 - Enhances regional consistency in the application of requirements for special inspection.
• 2308 - Provides greater seismic design requirements.
• 3109 - Provides enhanced regional consistency and safety protection of pool and spa users
• 3110 - Provides additional safety measures that reduce the risk of death or injury from gates that may detach from supporting hardware.
Appendix G – Flood Resistant Construction:
• Ensures local compliance with Federal Emergency Management Agency (FEMA) requirements of construction in flood plains.
23.29 WILDLAND-URBAN INTERFACE CODE
• The newly created Wildland-Urban Interface (WUI) Code addresses the growing risk of wildfire in areas where urban development meets or intermingles with wildland vegetation.
• Its purpose is to establish consistent construction and defensible space standards that enhance community resilience and reduce wildfire loss.
• The new California WUI Code consolidates provisions that were previously scattered across multiple codes, including:
• California Residential Code (CRC): Requirements for ignition-resistant construction, such as roofing, exterior walls, and vents. • California Building Code (CBC): Structural fire safety, materials testing, and performance-based design criteria.
• California Fire Code (CFC): Operational standards for defensible space, access, water supply, and vegetation management.
RECOMMENDATION
Adopt a Resolution to set forth express findings that amendments to the 2025 Building Standards Codes are reasonably necessary based on local climatic, topographical, or geological conditions; and, introduce an Ordinance to amend San Mateo Municipal Code Chapter 23 “Buildings and Construction” to adopt the 2025 Building Standards Code by reference with local amendments; amend various sections of San Mateo Municipal Code Title 23 “Buildings and Construction”; update procedural language and revise miscellaneous sections; add Chapter 23.29 “Wildland-Urban Interface Code”
Thank You
Michael Titsworth
Deputy Director and Building Official
Community Development Department
[email protected]
650-522-7195
Mary Eusebio
Deputy Building Official
Community Development Department
[email protected]
650-522-7194