What building codes apply in California?

Title 24 is the common name for the California Code of Regulations, Title 24, also known as the California Building Standards Code. It consists of 12 parts that govern the design and construction of buildings in California. These include the Building Code (Part 2), Residential Code (Part 2.5), Electrical Code (Part 3), Mechanical Code (Part 4), Plumbing Code (Part 5), Energy Code (Part 6), and Fire Code (Part 9).

California does not adopt the IBC directly. Instead, it publishes the California Building Code (CBC), which is based on the IBC but includes extensive state-specific amendments for seismic design, fire safety, and accessibility. The CBC is published as a 'State Edition' (Title 24, Part 2), meaning the state rewrites the code to fully integrate these changes rather than issuing a separate list of amendments.

The 2022 California Building Code (based on the 2021 IBC) became effective on January 1, 2023, and will remain in effect through December 31, 2025. Projects with permit applications submitted on or after January 1, 2026, must comply with the 2025 California Building Code (based on the 2024 IBC).

The California Residential Code (CRC/Title 24 Part 2.5) applies specifically to detached one- and two-family dwellings and townhouses up to three stories. The California Building Code (CBC/Title 24 Part 2) applies to all other structures, including multi-family apartment buildings, commercial properties, and institutional facilities. Both are state editions based on the IRC and IBC, respectively.

Yes, California enforces Title 24, Part 6 (California Energy Code), which is significantly more stringent than the International Energy Conservation Code (IECC) used in most other states. It mandates high-performance standards for building envelopes, HVAC systems, lighting, and specifically requires solar photovoltaic (PV) systems for new residential construction.

The California Electrical Code (Title 24, Part 3) is based on the National Electrical Code (NEC/NFPA 70). However, like other Title 24 parts, it is a state edition containing significant amendments. For example, the 2022 CEC is based on the 2020 NEC but includes unique California provisions for electric vehicle (EV) charging infrastructure and energy storage systems.

No. While the California Fire Code (CFC/Title 24 Part 9) is based on the International Fire Code (IFC), it includes major amendments tailored to California's specific risks, particularly regarding wildfire-urban interface (WUI) areas, fire sprinkler requirements, and vegetation management. It must be used in conjunction with Title 19 (Public Safety) regulations.

California is one of the few states that adopts the Uniform Plumbing Code (UPC) published by IAPMO, rather than the International Plumbing Code (IPC). The California Plumbing Code (CPC/Title 24 Part 5) is a state edition based on the UPC. Using the IPC in California is not permitted unless specifically allowed by local ordinance as an alternate method, which is rare.

California follows a triennial (3-year) code adoption cycle. New editions are usually published in July of the intervening year and become effective on January 1st of the following year. For example, the 2022 codes were published in July 2022 and became effective Jan 1, 2023. Intervening Code Adoption Cycles occur midway through to address urgent changes.

Because California publishes 'State Editions', the amendments are integrated directly into the code text of Title 24. You don't need to look for a separate amendment document to layer on top of the IBC; you should simply read the California Building Code itself. The California Building Standards Commission (CBSC) provides read-only access to these codes on their website.