# Montana Building Codes in 2026: Editions, Dates and AHJ > Montana's current 2021 I-Codes, June 2022 effective date, 2017 accessibility standard, 2019 elevator code and local-enforcement checks. - Canonical: https://harth.build/resources/building-codes/us-states/montana/ - Last updated: 2026-09-05 ## Direct answer and reference scope Montana Building Codes in 2026: Editions, Dates and AHJ is a Harth adoption and amendment guide for Montana. Montana's current 2021 I-Codes, June 2022 effective date, 2017 accessibility standard, 2019 elevator code and local-enforcement checks. Use the [Montana Department of Labor and Industry](https://bsd.dli.mt.gov/building-codes-permits/current-codes) to confirm the code edition currently adopted for the project, and compare the model text with state amendments, local amendments, effective dates and the permit authority's interpretation. The [ICC code library](https://codes.iccsafe.org/codes) is the model-code publication path. This Harth page summarizes adoption records and amendment sources; it does not reproduce the controlling code, provide a legal opinion or confirm which edition controls a particular address. Record the project jurisdiction, application date, occupancy, construction type and amendment set before relying on a section. Where this page conflicts with an official publication or the authority having jurisdiction, the official source controls. _Authored and prepared by Harth from the linked agency records. Review scope: adoption status and source paths verified; project-specific applicability and local interpretation require AHJ confirmation._ ## Direct answer Montana currently uses the **2021 International Building, Residential, Existing Building, Energy Conservation, Mechanical and Fuel Gas Codes**, all effective June 11, 2022 and amended through Administrative Rules of Montana Title 24, Chapter 301. Montana uses the 2021 Uniform Plumbing Code, 2020 NEC, ICC A117.1-2017 and ASME A17.1-2019 on the same current-code list. Montana published proposed 2024-edition amendments in 2026, but the proposal is not treated here as adopted law. Use the Department of Labor and Industry’s current-code page and final rule notice to identify when a new edition actually takes effect. ![Labeled code-chapter diagram: Montana Building Codes in 2026: Editions, Dates and AHJ](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/building-codes/us-states/montana/index/diagram-1344.webp) *Montana's current 2021 I-Codes, June 2022 effective date, 2017 accessibility standard, 2019 elevator code and local-enforcement checks.* ## Current Montana code matrix | Discipline | Current edition | Effective date | | --- | --- | --- | | Building | 2021 IBC | June 11, 2022 | | Residential | 2021 IRC | June 11, 2022 | | Existing buildings | 2021 IEBC | June 11, 2022 | | Energy | 2021 IECC | June 11, 2022 | | Mechanical | 2021 IMC | June 11, 2022 | | Fuel gas | 2021 IFGC | June 11, 2022 | | Plumbing | 2021 UPC | June 11, 2022 | | Electrical | 2020 NEC | June 11, 2022 | | Accessibility | ICC A117.1-2017 | June 11, 2022 | | Elevators | ASME A17.1-2019 | June 11, 2022 | | Existing elevators | ASME A17.3-2017 | June 11, 2022 | | Wildland-urban interface | 2021 IWUIC | June 11, 2022 | Source: [Montana DLI, Current Codes](https://bsd.dli.mt.gov/building-codes-permits/current-codes). Every listed code is subject to Montana amendments in ARM Title 24, Chapter 301. ## State or local enforcement? Montana’s Building Codes Program adopts the uniform state code and directly serves areas without a certified local program. Cities, counties and towns can operate certified building, electrical, plumbing and mechanical enforcement programs, but their adopted codes must stay within the state framework. State-owned agency projects remain with the state program. For each project, record: 1. whether the address is served by a [certified local enforcement program](https://bsd.dli.mt.gov/building-codes-permits/certified-city-county-and-town-programs); 2. the state and local amendment set; 3. the permit-application date and any transition rule; 4. the building official’s snow-load determination; and 5. discipline-specific permits handled by the state rather than the locality. ## Montana code-basis worksheet | Item | Project entry | | --- | --- | | Project address and jurisdiction | — | | State or certified local AHJ | — | | Building / residential / existing-building edition | — | | Energy, plumbing, mechanical and electrical editions | — | | Accessibility standard | — | | State and local amendments | — | | Ground and design snow-load basis | — | | Permit vesting / application date | — | | Written AHJ confirmation | — | The legacy 2009 energy-code material linked below is retained as a historical reference. It is **not** Montana’s current 2026 code basis. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/?context=%2Fresources%2Fbuilding-codes%2Fus-states%2Fmontana%2F - View this page in a browser: https://harth.build/resources/building-codes/us-states/montana/ - All resources for agents: https://harth.build/llms.txt