The building code in force in California now.

2025 California Building Code (Title 24, Part 2), based on the 2024 IBC with California amendments; Part 10 Existing Building Code from the 2024 IEBC

DGS states the 2025 edition takes effect Jan 1, 2026; the triennial cycle proposed adopting 2024 ICC and IAPMO model codes and the 2023 NEC. The 2025 Intervening Cycle supplements are scheduled to take effect Jul 1, 2027.

Source: primary document

Local city/county building departments; specified state agencies for state-regulated occupancies. Adopting body: California Building Standards Commission

Statewide layer. County and city amendments sit on top; confirm the local office for the address.

Supplement effective Jul 1, 2027

2025 Intervening Code Cycle supplements effective Jul 1, 2027 (BSC page re-read Oct 19, 2026; comment periods TBD)

• LA County Public Works Building and Safety Division is the building official for unincorporated areas; the City of Los Angeles and most incorporated cities run their own building departments under locally amended versions of the County Building Code.
• No county-wide periodic recertification law exists; the City of Los Angeles instead mandates a one-time seismic retrofit for pre-1978 wood-frame soft-story buildings and pre-1977 non-ductile concrete buildings, not a recurring inspection cycle.