Building codes & construction
Title 24 (California Building Standards Code)
California's statewide construction code: 12 parts of building, residential, energy, green and fire standards. The 2025 edition took effect January 1, 2026.
Definition
Title 24 of the California Code of Regulations is the California Building Standards Code — the statewide construction code, adopted by the Building Standards Commission on a three-year cycle. It spans 12 parts, from the Administrative Code (Part 1) to the Referenced Standards Code (Part 12), including the Building Code (Part 2), the Residential Code (Part 2.5), the Mechanical (Part 4) and Plumbing (Part 5) Codes, the Energy Code (Part 6), and the Fire, Existing Building and Green Building (CALGreen) parts. The 2025 edition — which added a new Wildland-Urban Interface Code (Part 7.5) — took effect January 1, 2026.
Why it matters in an underwrite
Every California building permit is checked against the Title 24 edition in effect when the application is filed, so a project filing on or after January 1, 2026 is designed to the 2025 code — new energy baselines, EV infrastructure counts and wildfire provisions included. Which parts bind which scope (CBC vs. CRC, CALGreen tiers, local amendments layered on top) is one of the first cost questions an underwrite should answer.
Sources & related guides
See also
See the term in the law itself
Read the controlling text in the Code Library, or ask the AI how it applies to your project.
Last reviewed 2026-07-29. General information, not legal advice.