Michigan mechanical, plumbing, fuel gas & energy codes
Michigan has a single state construction code (Stille-DeRossett-Hale Act) administered by LARA's Bureau of Construction Codes. Commercial work follows the Michigan Mechanical and Plumbing Codes. One- and two-family dwellings follow the Michigan Residential Code.
Quick answer: Michigan currently uses the 2021 IMC for mechanical work and the 2021 IPC for plumbing (see sources and dates below). A2L status: Allowed: 2021 MMC adopts ASHRAE 15-2022
Adopted codes
Mechanical
2021
IMC
- Adopted as
- 2021 Michigan Mechanical Code (Part 9A, R 408.30901a)
- Effective
- 2024-03-12
- Source
- LARA – Code Books
- Last checked
- 2026-10-29 verified
- Notes
- Adopts the 2021 IMC (third printing) with Michigan amendments. Residential requirements are in the Michigan Residential Code.
Plumbing
2021
IPC
- Adopted as
- 2021 Michigan Plumbing Code (Part 7, R 408.30701)
- Effective
- 2024-03-12
- Source
- LARA – Code Books
- Last checked
- 2026-10-29 verified
- Notes
- Adopts the 2021 IPC (second printing) with Michigan amendments.
Fuel Gas
2021 MMC
IMC-based Michigan code
- Adopted as
- Michigan Mechanical Code (covers gas piping)
- Effective
- 2024-03-12
- Source
- LARA – 2021 Part 7 Plumbing Rules, Sec. 101.2
- Last checked
- 2026-10-29 verified
- Notes
- Michigan Plumbing Code 101.2 sends gas piping design and installation to the Michigan Mechanical Code. We haven't confirmed whether, or which edition of, the IFGC is incorporated.
Energy
Residential: 2015 IECC; Commercial: 2021 IECC & ASHRAE 90.1-2019
IECC / ASHRAE 90.1
- Adopted as
- State energy code (per U.S. DOE BECP)
- Effective
- Res 2016-02-08; Com 2025-04-22
- Source
- U.S. DOE Building Energy Codes Program – Michigan
- Last checked
- 2026-10-29 verified
- Notes
- Commercial: 2021 Michigan Commercial Energy Code (effective Apr 22, 2025).
A2L refrigerants in Michigan
Michigan's Part 9A rules adopt ASHRAE 15-2022, ASHRAE 34-2022 and UL/CSA 60335-2-40-2022 with the 2021 Michigan Mechanical Code (effective Mar 12, 2024). That gives a code path for A2L equipment even though the base IMC is 2021.
Source: https://ars.apps.lara.state.mi.us/AdminCode/DownloadAdminCodeFile?FileName=R+408.30901++to+408.30998.pdf&ReturnHTML=True · Last checked 2026-10-29 verified
Local amendments & things to watch
- One- and two-family dwellings follow the 2015 Michigan Residential Code (effective Feb 8, 2016), which is older than the commercial mechanical and plumbing codes. verified source
- Commercial energy moved to the 2021 Michigan Commercial Energy Code on Apr 22, 2025, and the 2021 Michigan Building Code took effect Apr 9, 2025. verified source