For a building permit in Montana, check that the code analysis cites the state building code in ARM Title 24, Chapter 301, which since September 26, 2026 has adopted the 2024 IBC, IRC, IEBC, IECC, IMC, IFGC, and ISPSC, the 2024 Uniform Plumbing Code, and the 2023 NEC, each with Montana amendments. Then confirm whether a certified city, county, or town or the state Building Codes Program reviews each discipline, since a local program may be certified for only some codes and has a set period to conform to new editions. AI can flag conflicts; the design professional and the building official decide compliance.
Which Montana codes apply to a set of drawings?
Under MCA 50-60-203, the Department of Labor and Industry adopts by rule the state building code for the construction of buildings, including safety, accessibility, sanitation, and energy conservation, and may adopt nationally recognized codes by reference. The same section bars it from requiring fire sprinklers in one- and two-family dwellings, from requiring solar panels or equipment for solar panels or electric vehicles, and from prohibiting or limiting any energy source, and it directs the department to permit Group R-2 buildings with a single exit stairway when listed conditions are met. The department’s Building Codes Program adopts the codes in ARM Title 24, Chapter 301: the IBC with Appendix C (24.301.131) and the amendments that apply to both state and local programs (24.301.146), the IRC (24.301.154), the IECC (24.301.161), the IEBC (24.301.171), the IMC (24.301.172), the IFGC (24.301.173), the ISPSC (24.301.175), the International Wildland-Urban Interface Code (24.301.181), the Uniform Plumbing Code (24.301.301), and the NEC (24.301.401). ARM 24.301.201 treats the IBC as including ICC A117.1, the IECC, the ISPSC, and the IEBC, and the IRC as including the IECC. The program’s code list does not include the International Fire Code, and ARM 24.301.146 replaces the IBC’s references to it with the fire code adopted by the fire authority having jurisdiction.
The program’s Current Codes page lists the 2024 IBC, IRC, IEBC, IECC, IMC, IFGC, and ISPSC, the 2024 Uniform Plumbing Code, the 2023 NEC, and ICC A117.1-2017, all effective September 26, 2026, and NFPA 99-2018 for medical gas since June 11, 2022. The rule histories on rules.mt.gov show each amendment under MAR Notice No. 2026-95 effective that day, and the prior versions adopted the 2021 IBC, IRC, IECC, and UPC and the 2020 NEC through September 25, 2026. ARM 24.301.181 also adopts the 2024 IWUIC, with Appendices B and C, for wildland-urban interface areas that a state or local agency declares, and local programs that elect to enforce it must map those areas, although the Current Codes page does not list it. All checked October 30, 2026.
Two rules govern the changeover. ARM 24.301.146 says a building or project with a legal building permit issued before new codes take effect does not have to meet them, and the building official decides case by case whether a permit process was substantially complete. ARM 24.301.202 gives certified cities, counties, and towns 90 days from the department’s notice to conform their codes, so confirm which edition a local program enforces on your application date.
The Montana amendments change what a reviewer should expect to see. The IRC rule deletes IRC Chapters 11 through 14 and 16 through 43, so dwellings take energy, mechanical, plumbing, and electrical requirements from the IECC, IMC, UPC, and NEC, with IRC Chapter 15 kept as an alternative for exhaust systems, and it deletes the dwelling sprinkler section. The IECC rule deletes commercial sections including C405.12 automatic receptacle control, C405.13 energy monitoring, C405.15 renewable energy systems, and C406, and deletes some provisions, such as C402.7 thermal bridges, only where the department enforces the code. The IBC amendments replace the plumbing fixture table with ARM 24.301.351, replace International Plumbing Code references with the UPC, set NFPA 13 and 13R at the 2022 edition and NFPA 14 at the 2024 edition for Chapter 9, and have the building official determine snow loads, using ASCE/SEI 7-22 outside certified jurisdictions. Under the IEBC rule, an owner follows either the IEBC or the IBC for work on an existing building, not parts of each.
Review depends on location and discipline. Under MCA 50-60-301 a county, city, or town may adopt a building code but may not adopt or enforce one more stringent than the department’s, apart from voluntary incentive-based energy standards, and under MCA 50-60-302 it may not enforce any code until the department certifies its program. The certified jurisdiction list shows which building, plumbing, electrical, mechanical, swimming pool, and wildland codes each program enforces and says all other areas fall under the state program, and ARM 24.301.201 keeps the department’s authority over the buildings and disciplines a local program is not certified for. The program’s home page says state-owned agencies must be permitted through the department. MCA 50-60-102 exempts farm and ranch buildings, private garages and storage buildings for the owner’s own use, and residential buildings below the unit count it sets from the state building code unless a local ordinance covers them, but the energy provisions still apply to residential buildings, through builder self-certification for the smaller ones. The building permits page adds that the residential exemption does not cover buildings serving transient guests, and that the building permit must be issued before plumbing, mechanical, or electrical permits. The program’s commercial plan review submittal requirements list the site plan, floor plans with schedules, wall sections, framing and truss drawings, foundation and egress plans, elevations, and REScheck or COMcheck. Permit routing is on the Montana page, and the model codes have their own guides: IBC, IRC, IECC, UPC, and NFPA 70.
Gather the code analysis, the permit status, and each discipline’s Montana references
Collect the cover sheet and code analysis with the codes and editions cited, the site plan with property lines and adjacent buildings, floor plans with door and window schedules and the egress plan, wall sections, floor and roof framing and truss drawings, the foundation plan, elevations, structural general notes with the snow and seismic design basis, the mechanical, fuel gas, plumbing, and electrical drawings with the plumbing fixture calculation, sprinkler and standpipe notes, the COMcheck or REScheck, and the specifications.
Add the project location and whether a certified local program covers it and for which codes, whether the building is state-owned, whether it is exempt under MCA 50-60-102 or serves transient guests, the permit application date and any permit issued before September 26, 2026, whether the site is in a declared wildland-urban interface area, the fire code the fire authority applies, and, for existing buildings, whether the owner follows the IEBC or the IBC. Download the ARM rules you rely on from rules.mt.gov.
Trace the ARM 24.301 codes through the set
| Review question | Sources to compare | Decision to record |
|---|---|---|
| Code editions and permit date | Cover sheet, code analysis, general notes, ARM 24.301 rules, permit status | Confirm the 2024 IBC, IRC, IEBC, IECC, IMC, and IFGC, the 2024 UPC, and the 2023 NEC are cited, or record the building official’s decision for a permit issued, or substantially complete, before September 26, 2026. |
| Plumbing and residential paths | Plumbing drawings, fixture calculation, IRC sheets, mechanical notes | Check that plumbing cites the UPC and the fixture rule in ARM 24.301.351, not the IPC, and that dwelling sheets take energy, mechanical, plumbing, and electrical requirements from the IECC, IMC, UPC, and NEC. |
| Energy amendments | COMcheck or REScheck, lighting and receptacle control plans, electrical and solar notes | Match the energy documents to the 2024 IECC as amended in ARM 24.301.161, and flag requirements attributed to deleted sections such as C405.12, C405.13, C405.15, and C406. |
| Existing building path | Scope of work, code analysis, existing and proposed plans | Record whether the owner follows the IEBC or the IBC, and flag sheets that apply requirements from both on the same project. |
| Reviewing program by discipline | Project location, certified jurisdiction list, ownership, exemption status | Record which codes the certified city, county, or town enforces and which permits come from the state Building Codes Program, which permits all state-owned buildings. |
| Fire protection and snow load basis | Sprinkler and standpipe notes, structural design criteria, fire authority | Confirm NFPA 13 and 13R at the 2022 edition and NFPA 14 at the 2024 edition for IBC Chapter 9, the fire code the fire authority applies, and a snow load basis the building official accepts. |
Plumbing sheets continue in the UPC guide and the plumbing drawing checklist, sprinkler and standpipe notes in the NFPA 13, NFPA 13R, and NFPA 14 guides, snow load criteria in the ASCE 7 guide, interface areas in the IWUIC guide, pools in the ISPSC guide, accessible details in the ICC A117.1 guide, and the full set in the architectural drawing checklist. Other western state codes are in the Utah guide, the Washington guide, and the Oregon structural code guide.
Example: a commercial set drawn to the 2021 codes and the IPC
Hypothetical example. A two-story retail and office building on a lot outside any certified local jurisdiction in Montana is designed in summer 2026 by a team that usually works under the International Plumbing Code, and the permit application goes to the state Building Codes Program in October 2026. The code analysis cites the 2021 IBC and IECC, the electrical notes cite the 2020 NEC, the plumbing sheets count fixtures from the IPC table, and the electrical plans show automatic receptacle controls and a rooftop solar array labelled as required by the IECC.
The code analysis cites the 2021 IBC and IECC and the electrical notes cite the 2020 NEC, while ARM 24.301.131, 24.301.161, and 24.301.401 adopt the 2024 IBC and IECC and the 2023 NEC effective September 26, 2026, and no building permit was issued before that date. The plumbing fixture count follows the IPC, while Montana uses the Uniform Plumbing Code and the fixture rule in ARM 24.301.351. The electrical plans attribute automatic receptacle control and a rooftop solar array to the IECC, but ARM 24.301.161 deletes Sections C405.12 and C405.15. Confirm the governing editions with the Building Codes Program and coordinate the code analysis, plumbing, electrical, and energy documents.
The architect confirms with the Building Codes Program that the application is reviewed under the 2024 codes, revises the code analysis, fixture calculation, electrical notes, and COMcheck, and the owner decides whether to keep the receptacle controls and solar array as voluntary features. The finding is a citation conflict; the building official decides compliance.
Review a Montana set with Groundbook
Upload the current drawings and specifications to Groundbook, and state the edition, amendments, and review scope in your instructions. The Administrative Rules of Montana are free on rules.mt.gov, and the Building Codes Program publishes its current codes list, certified jurisdiction list, and commercial plan review submittal requirements. Upload the ARM Title 24, Chapter 301 rules your project relies on as code files, with the 2024 International Codes, the 2024 Uniform Plumbing Code, and the 2023 NEC from copies you are licensed to use where the license permits uploading them. See how Groundbook works with local and licensed codes.
Compare the cover sheet, code analysis, and every discipline’s general notes with the architectural, structural, accessibility, mechanical, fuel gas, plumbing, electrical, fire protection, and energy documents. Flag citations to 2021 editions of the IBC, IRC, IEBC, IECC, IMC, IFGC, or UPC or to the 2020 NEC unless my instructions say the permit predates September 26, 2026, any reference to the International Plumbing Code, dwelling sheets that rely on IRC chapters the supplied ARM 24.301.154 deletes, energy requirements attributed to IECC sections the supplied ARM 24.301.161 deletes, existing building work that mixes IEBC and IBC requirements, and sprinkler or standpipe notes that cite NFPA editions other than those in ARM 24.301.146. Use the supplied ARM rules and model codes and cite both sources.
Groundbook links each potential finding to the note or sheet and to the ARM rule or model code you uploaded. It compares what the documents state; it does not decide which program reviews a discipline, whether a building is exempt, or which edition a permit falls under.
Document review does not certify compliance, issue a permit, or replace the design professional, the certified local building official, the Building Codes Program, or the fire authority having jurisdiction.