Idaho Building Code: Which Editions Are Adopted

Direct answer

2018 I-Codes as the Idaho building codes, applied by every local government that enforces building codes in Idaho. 2018 IBC, IRC (as the Idaho Residential Code), IEBC and IECC with Idaho Building Code Board amendments, plus the IFC adopted by the State Fire Marshal. The Idaho Building Code Board adopted the 2024 I-Codes with amendments (Docket 24-3930-2502), but the House Business Committee rejected the rule on 17 February 2026, so the 2018-based codes remain in force. Record the permit application date with it: a code change normally applies from an effective date, and an application filed before that date is usually reviewed under the previous edition. This was checked on 2026-10-01 against Idaho Building Code Board, Division of Occupational and Professional Licenses, 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 Idaho adopted now?

2018 I-Codes as the Idaho building codes, applied by every local government that enforces building codes.

2018 IBC, IRC (as the Idaho Residential Code), IEBC and IECC with Idaho Building Code Board amendments, plus the IFC adopted by the State Fire Marshal.

Transition: The Idaho Building Code Board adopted the 2024 I-Codes with amendments (Docket 24-3930-2502), but the House Business Committee rejected the rule on 17 February 2026, so the 2018-based codes remain in force.

Local adoption: Building code enforcement is optional for cities and counties. Those that issue building permits must adopt the editions set by the Idaho Building Code Board, effective 1 January of the year after the Board adopts them. Local governments may not adopt residential or residential energy provisions the Board has not adopted, and state law bars any local energy requirement stricter than the Idaho Energy Conservation Code.

Checked 2026-10-01 against Idaho Building Code Board, Division of Occupational and Professional Licenses. 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 Idaho. Where this disagrees with the record above, the record above is newer:

Idaho has a recorded edition year for 8 of the 17 codes: 2018 for the building, residential, fire, mechanical, fuel gas, residential energy, commercial energy and existing buildings codes. The green construction, property maintenance, wildland-urban interface and green building standard 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. No adoption at all is recorded for the plumbing, private sewage, performance and zoning codes.

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

How Idaho 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.

Washington, Oregon, Montana and Utah differ from Idaho on the building code alone. A practice working across that border is working to two editions, whatever the office standard says.

Where Idaho sits in the national record

Idaho is one of 17 jurisdictions with no statewide IBC edition in force. Adoption runs through local programmes or applies only to a subset of buildings, so there is no single answer for the state and the permit jurisdiction for the address decides.

Idaho 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, Idaho has a recorded edition for 8, which ranked it 20th 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 Idaho project

1. Open Idaho Building Code Board, Division of Occupational and Professional Licenses 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.

Idaho 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
• Washington Building Code: Which Editions Are Adopted
• Oregon Building Code: Which Editions Are Adopted
• Montana Building Code: Which Editions Are Adopted
• Utah 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 Idaho Building Code Board, Division of Occupational and Professional Licenses, which controls.

Source links

• iccsafe.org

• iccsafe.org

• adminrules.idaho.gov