California Building Code: Which Editions Are Adopted

Direct answer

2025 California Building Standards Code (Title 24), effective 1 January 2026 in California. 2024 IBC, IRC and IFC with California amendments, plus the state's own Energy Code (Title 24, Part 6) and CALGreen. The 2025 code applies to permit applications filed on or after 1 January 2026. Under AB 130 (2025), state and local agencies may not adopt new building standards affecting residential units from 1 October 2025 to 1 June 2031, with narrow exceptions such as emergency standards and wildfire home hardening. Title 24 applies statewide. Cities and counties may adopt local amendments filed with the Building Standards Commission, but residential amendments are largely frozen under AB 130. This was checked on 2026-10-01 against California Building Standards Commission, which is the source that controls. The cross-state comparison further down this page comes from the ICC adoption chart dated January 2024, so where the two disagree the record above is the newer one.

Content and cited inputs reviewed by Harth team · Published 2026-09-07 · Updated 2026-10-01.

Which codes has California adopted now?

2025 California Building Standards Code (Title 24), effective 1 January 2026.

2024 IBC, IRC and IFC with California amendments, plus the state's own Energy Code (Title 24, Part 6) and CALGreen.

Transition: The 2025 code applies to permit applications filed on or after 1 January 2026. Under AB 130 (2025), state and local agencies may not adopt new building standards affecting residential units from 1 October 2025 to 1 June 2031, with narrow exceptions such as emergency standards and wildfire home hardening.

Local adoption: Title 24 applies statewide. Cities and counties may adopt local amendments filed with the Building Standards Commission, but residential amendments are largely frozen under AB 130.

Checked 2026-10-01 against California Building Standards Commission. Confirm the edition and effective date for the specific permit jurisdiction before relying on it.

The cross-state record

For comparison across states, every I-Code the ICC Master I-Code Adoption Chart (January 2024) tracks, as it records California. Where this disagrees with the record above, the record above is newer:

California has a recorded edition year for 4 of the 17 codes: 2021 for the building, residential, fire and existing buildings codes. The property maintenance, swimming pool and spa and wildland-urban interface codes appear as adopted by individual state or local agencies rather than as a statewide standard, so whether they apply depends on the permit jurisdiction for the project address. California publishes its own document in place of the model text for the residential energy and commercial energy codes, so the model edition is a reference rather than the enforced text. No adoption at all is recorded for the mechanical, plumbing, private sewage, fuel gas, green construction, performance, zoning and green building standard codes.

Source: ICC Master I-Code Adoption Chart (January 2024).

How California compares with its neighbours

Statewide editions in force, checked 2026-10-01; “Local” means no state adoption, “(limited)” a state adoption for some buildings only, and * a state-titled code built on that edition.

Nevada, Arizona and Washington differ from California on the building code alone. A practice working across that border is working to two editions, whatever the office standard says.

Where California sits in the national record

Of the 50 states and the District of Columbia, 10 enforce the 2024 IBC statewide, 0 a later edition, 24 an earlier one, and 17 have no statewide IBC edition in force. California is at or ahead of the national middle on the building code, so the risk runs the other way: work arriving from a slower-moving state may be drawn to an older edition.

California is one of 15 jurisdictions with no statewide residential energy code based on an IECC edition in force, so the energy question is answered by the state's own document or by the local jurisdiction.

Across all 17 codes the January 2024 ICC chart tracks, California has a recorded edition for 4, which ranked it 43rd of 51. A low count is not a gap in regulation — it usually means the state legislates through its own documents, or leaves the discipline to local adoption.

What the chart does and does not tell you

The chart's own legend matters more than the numbers:

• An edition year means one or more state or local agencies adopted that edition. It does not mean every building in the state is designed to it.
• “Some jurisdictions only” is the chart's X: the code is in use somewhere in the state but is not the standard for all buildings.
• “Not adopted” is a blank cell — no state or local jurisdiction reported adopting that code.
• “State-written code” means the state publishes its own document in place of the model edition, so the model text is a reference, not the law.

ICC states plainly that not every jurisdiction notifies it of an adoption, and this chart is dated January 2024. Treat it as the starting point for a search, never as the answer.

How to confirm the edition that governs a California project

1. Open California Building Standards Commission and find the currently adopted code list with its effective date.
2. Check whether the permit authority for the project address is the state or a local programme with its own adoption.
3. Read the state amendments alongside the model edition — an amended table or definition changes the requirement even when the edition matches.
4. Record the permit application date. A code change usually applies from an effective date, and applications filed before it are normally reviewed under the previous edition.
5. Get the answer in writing from the authority having jurisdiction before it drives a design decision.

California code-basis worksheet

Fill this in once per project and keep it with the drawing set. Every row is a question a plan reviewer can ask, and the answer changes with the address and the application date, not with the state.

This worksheet records a determination; it does not make one. The authority having jurisdiction decides which edition and which amendments apply.

Where can you explore related guidance?

• Explore all code adoption guidance
• Nevada Building Code: Which Editions Are Adopted
• Oregon Building Code: Which Editions Are Adopted
• Arizona Building Code: Which Editions Are Adopted
• Washington Building Code: Which Editions Are Adopted

Sources and method

Adopted editions transcribed from the ICC Master I-Code Adoption Chart (January 2024), reproduced with the chart's own legend so an “X” is not mistaken for a statewide adoption. ICC notes that not all jurisdictions report their adoptions and publishes updates at iccsafe.org/adoptions. The current edition, its effective date and the state amendments are published by California Building Standards Commission, which controls.

Source links

• iccsafe.org

• iccsafe.org

• dgs.ca.gov