Massachusetts mechanical, plumbing, fuel gas & energy codes
The Massachusetts State Building Code (780 CMR, 10th edition) is adopted by the Board of Building Regulations and Standards (BBRS) and applies statewide. Plumbing and fuel gas are separate state-written codes (248 CMR) from the Board of State Examiners of Plumbers and Gas Fitters.
Quick answer: Massachusetts currently uses the 2021 IMC for mechanical work and the 248 CMR 10.00 State-written code for plumbing (see sources and dates below). A2L status: AHJ approval path (BBRS advisory, Nov 12, 2024)
Adopted codes
Mechanical
2021
IMC
- Adopted as
- 780 CMR 10th Edition (Mass. State Building Code)
- Effective
- 2024-10-11
- Source
- Mass.gov – Tenth edition of the MA State Building Code
- Last checked
- 2026-10-29 verified
- Notes
- With MA amendments. The 9th-edition concurrency period ended June 30, 2025. Sheet-metal work falls under its own specialized code.
Plumbing
248 CMR 10.00
State-written code
- Adopted as
- 248 CMR 10.00 Uniform State Plumbing Code
- Effective
- 2023-12-08
- Source
- Mass.gov – 248 CMR 10.00
- Last checked
- 2026-10-29 verified
- Notes
- Massachusetts writes its own plumbing code. The current text is the Dec 8, 2023 revision (Mass. Register #1510), and 780 CMR sends IPC references to 248 CMR.
Fuel Gas
NFPA 54-2012
NFPA 54 (as amended by 248 CMR 5.00)
- Adopted as
- 248 CMR 4.00–8.00 Massachusetts Fuel Gas Code
- Effective
- 2021-04-30
- Source
- Mass.gov – 248 CMR 4.00
- Last checked
- 2026-10-29 verified
- Notes
- Adopts the 2012 edition of NFPA 54 and the 2011 edition of NFPA 58 (current text dated Mass. Register #1442, 4/30/21). The IFGC isn't used.
Energy
Residential: 2021 IECC; Commercial: 2021 IECC & ASHRAE 90.1-2019
IECC / ASHRAE 90.1
- Adopted as
- State energy code (per U.S. DOE BECP)
- Effective
- Res 2024-10-11; Com 2024-10-11
- Source
- U.S. DOE Building Energy Codes Program – Massachusetts
- Last checked
- 2026-10-29 verified
- Notes
- Base energy code in 780 CMR, with MA amendments.
A2L refrigerants in Massachusetts
The 2021 IMC in the 10th edition doesn't accommodate A2Ls, but 780 CMR 2802 adopts ASHRAE 15-2022, ASHRAE 34-2022 and UL/CSA 60335-2-40-2022. The BBRS advises that A2L installations meeting those standards are 'readily approvable' by the building official as alternatives under 780 CMR 104.11, and it plans to update the code.
Source: https://www.mass.gov/doc/2024-01-a2l-refrigerants-advisory/download · Last checked 2026-10-29 verified
Local amendments & things to watch
- Fuel gas is still on NFPA 54-2012, even though NFPA has since published the 2015, 2018, 2021 and 2024 editions. Gas piping is capped at 0.5 psig unless designed under 248 CMR 5.05(4)(B). verified source
- Many cities and towns have opted into the Stretch Energy Code or the Specialized Opt-in Code, which go beyond the base energy code. Check the municipality. unverified