California Administrative Code (CAC)

The California Administrative Code (CAC) is Part 1 of the California Building Standards Code (Title 24, California Code of Regulations). Unlike the technical parts of Title 24, Part 1 does not set construction standards — it sets the administrative regulations and procedures that govern how every other part of Title 24 is proposed, adopted, amended, published and enforced. It is the rulebook for the rulebook, and it is published and maintained by the California Building Standards Commission (BSC) within the Department of General Services.

The 2025 California Administrative Code is the current edition, effective January 1, 2026, replacing the 2022 CAC. Title 24 is updated on a three-year (triennial) cycle, and state agencies such as HCD, DSA and HCAI propose amendments that the BSC approves and codifies. Local jurisdictions then adopt the statewide code and may add their own amendments — so the controlling rules for a project depend on the adopted edition and any local changes, which is exactly what GoCodebook reconciles for you.

Part 1 answers the questions that come up when a rule is disputed rather than merely applied: which edition governs my permit, can my city require more than the state, which agency wrote this provision, and how do I appeal an interpretation. Those answers are procedural, and they live here rather than in any technical code.

Part 1 establishes the procedures and authority behind Title 24. It defines how proposed building standards move through rulemaking, how public comment is handled, how standards are codified into the California Code of Regulations, and how the resulting code is enforced by local building departments. It also contains the matrix adoption tables that show which state agency adopted a given provision and which occupancies it applies to — a key tool for tracing the origin of any requirement in the technical parts of Title 24.

Because the CAC governs process rather than physical construction, it is most often consulted to answer questions about which edition applies, when it takes effect, who has authority, and how amendments are made. Those answers in turn determine how to read the California Building Code (CBC, Part 2) and every other technical part. See where GoCodebook coverage is deepest.

Several state agencies write the building standards that the Building Standards Commission adopts into Title 24. The Department of Housing and Community Development (HCD) develops standards for residential occupancies, including the California Residential Code (CRC, Part 2.5), ADUs and manufactured housing. The Division of the State Architect (DSA) develops accessibility and K–12 school and community-college standards. The Department of Health Care Access and Information (HCAI, formerly OSHPD) develops standards for hospitals and skilled-nursing facilities.

Other proposing agencies include the California Energy Commission for the Electrical and Energy provisions, and the Office of the State Fire Marshal for fire and life-safety standards. The CAC documents each agency's authority and the matrix tables that map provisions back to the agency that adopted them — so you always know who is responsible for a given rule.

California adopts a new edition of Title 24 on a three-year cycle. The 2025 code was published July 1, 2025 and became effective January 1, 2026, replacing the 2022 edition. The CAC sets out the timeline for this process — pre-cycle activities, the 45-day public comment period, code advisory committee review, and BSC adoption. The 2025 cycle was generally a minor revision, with administrative updates that codify current practices and procedures.

Once the statewide edition is published, cities and counties adopt it locally and may add amendments justified by local climatic, geological or topographical conditions. That means two neighboring jurisdictions can enforce different versions of the same provision. GoCodebook identifies the adopted edition and local amendments for your address and returns the governing rule with a citation. Compare with the GoCodebook answer engine across the full CBC and sibling codes.

Every technical part of Title 24 opens its chapters with a matrix adoption table — a grid showing which state agency adopted which chapter or section, for which occupancies. Provisions are also marked in the text with bracketed agency banners such as [BSC], [HCD 1], [DSA-SS], [HCAI 1] or [SFM].

Reading those markers correctly is the difference between applying a rule and applying the wrong rule. A section banded [DSA-SS] applies to public schools and community colleges; one banded [HCAI 1] applies to general acute care hospitals; one banded [HCD 1] applies to housing. A private office building is not governed by any of them, even though all three sit in the same chapter.

Part 1 is where the authority for those bands is established, along with the roles of the Building Standards Commission and the proposing agencies — HCD, DSA, HCAI (formerly OSHPD), the State Fire Marshal, BSCC, DPH and others.

Title 24 runs on a triennial cycle, with each edition effective January 1 following its publication year. Between full editions the Commission publishes intervening code adoption cycle supplements — usually effective July 1 — that can change requirements mid-cycle. A project team that only tracks full editions can miss a change that is already in force.

Local jurisdictions must adopt the statewide code, and may adopt amendments more restrictive than Title 24 only by making express findings that local climatic, geological or topographical conditions justify them and filing those findings with the state — the mechanism in Health and Safety Code section 17958.5. That filing requirement is what makes local amendments findable and, occasionally, challengeable.

Part 1 also covers appeals and alternate means: how a local board of appeals is constituted, and how an alternate material, design or method of construction is proposed and approved when it is not covered by prescriptive text.

California's adopted codes — including the California Administrative Code (CAC) — are published under Title 24 and hosted on code libraries such as UpCodes (up.codes) and ICC Digital Codes from the International Code Council (ICC). Those let you read the text section by section.

GoCodebook goes further: instead of searching a code library, you ask a question and get the controlling provision for the edition and local amendments your jurisdiction adopted, with a citation to verify. See how GoCodebook compares to UpCodes and ICC.