Massachusetts enforces the 2021 IECC residential

Record of adoption

In force since

Oct 11, 2024

Legal citation

780 CMR Chapter 11R

Adopted by

Board of Building Regulations and Standards (BBRS), in consultation with the Department of Energy Resources (DOER)

Second reading

Agreed Oct 18, 2026

Applies

Statewide

Also called

Base Energy Code, Stretch Energy Code (225 CMR Chapter 22), Specialized Opt-in Code (225 CMR Chapter 22 + Appendix RC)

DOER names the base code as IECC 2021 with MA amendments; the effective date is that of the 10th Edition (concurrency with the 9th Edition ended Jun 30, 2025).

Exceptions

• Municipalities may opt in to the Stretch Energy Code (225 CMR Chapter 22) or the Specialized Opt-in Code (225 CMR Chapter 22 + Appendix RC), both promulgated by DOER (G.L. c. 25A, s. 6(14); G.L. c. 143, s. 96).
• Up to ten municipalities in DOER’s Fossil Fuel Free Building Demonstration Program (St. 2022, c. 179, s. 84; 225 CMR 24.00) may restrict fossil fuels in new construction and major renovations: Acton, Aquinnah, Arlington, Brookline, Cambridge, Concord, Lexington, Lincoln, Newton, plus Northampton as a substitute selection.

Coming next

• 2024 IECCPartial
  No date yetIn development780 CMR Chapter 11R (11th Edition, in drafting)

  The BBRS 11th Edition Energy Advisory Subcommittee (Dec 3, 2025) discussed the 2024 IECC with DOER amendments and noted the 2027 IECC may be published before adoption takes effect; no adoption or effective date was found. DOER also proposed 2026 revisions to the 2021-based Stretch and Specialized codes.

How Massachusetts adopts the IECC residential

• More than one path
• The legislature sets the update schedule
• A recent law changed the process

The BBRS adopts the energy chapters of 780 CMR (11R and 13) by regulation in consultation with DOER; G.L. c. 143, s. 94(o) requires it to adopt and fully integrate the latest IECC and to update within 1 year of any IECC revision. DOER separately promulgates the opt-in Stretch and Specialized codes (225 CMR 22.00 and 23.00; G.L. c. 25A, s. 6(14), as amended by St. 2021, c. 8), which municipalities adopt by local vote. No legislative approval of the rules is required; pending bill H.5175 would rewrite the s. 6(14) clause.

Cycle. Tied to 780 CMR editions: the base code moved to the 2021 IECC with the 10th Edition (Oct 11, 2024); a 2024 IECC update is in 11th Edition drafting. Stretch and Specialized codes were last updated in February 2025, with 2026 revisions proposed.

Laws, rulings, and other actions

1. Jul 16, 2026Legislation
   H.5175, An Act relative to energy affordability, clean power and economic competitiveness194th General Court, 2025-2026

   Omnibus energy bill whose Section 5 rewrites G.L. c. 25A, s. 6, cl. 14 (DOER’s municipal opt-in specialized stretch energy code).

   Pending (in conference committee as of Jul 16, 2026)

   malegislature.gov (opens in a new tab)
2. Jun 16, 2026Other action
   DOER proposed revisions to the Stretch and Specialized energy codes

   DOER held a public hearing on Jun 16, 2026 (comments to Jun 24, 2026) on proposed revisions to the opt-in Stretch and Specialized codes; BBRS minutes of Feb 10, 2026, mention a new six-month concurrency period.

3. Dec 5, 2024Other action
   BBRS extension of the 9th/10th Edition concurrency period

   After a BBRS hearing on Dec 2, 2024, the concurrency period originally set to end Jan 1, 2025, was extended to Jun 30, 2025 (announced Dec 5, 2024); only the 10th Edition applies after that.

4. Aug 11, 2022Legislation
   St. 2022, c. 179, An Act Driving Clean Energy and Offshore Wind (s. 84)

   Section 84 lets not more than ten cities and towns adopt local restrictions on fossil fuels in new construction and major renovations under DOER’s demonstration program (225 CMR 24.00).

   Enacted Aug 11, 2022 (date from the legislature page metadata, not labeled as an approval date)

   malegislature.gov (opens in a new tab)
5. Mar 26, 2021Legislation
   St. 2021, c. 8, An Act Creating a Next-Generation Roadmap for Massachusetts Climate Policy

   Directs DOER, with the BBRS, to develop a municipal opt-in specialized stretch energy code (G.L. c. 25A, s. 6(14)), adds it to the specialized codes in G.L. c. 143, s. 96, enlarges the BBRS from 11 to 15 members and changes a timing phrase in s. 97 to 45 days.

   Enacted Mar 26, 2021 (date from the legislature page metadata)

   malegislature.gov (opens in a new tab)
6. UndatedLegislation
   G.L. c. 143, s. 94(o) (energy provisions of the state building code); DOER attributes the requirement to the Green Communities Act of 2008 (St. 2008, c. 169)

   Requires the BBRS to adopt and fully integrate the latest IECC into the state building code and to update the energy provisions within 1 year of any IECC revision.

   Enacted 2008, per DOER’s description

   malegislature.gov (opens in a new tab)

How it was checked

Verified

Two separate readings of the state’s own record agree, and the passage is on file word for word.

Read twice: a second, blind reading of the state’s record agreed with the first on Oct 18, 2026.

The state’s record was last read on Oct 18, 2026, from four source pages.

Evidence 5 sources

Sources for the record itself come first, the state’s own records ahead of others. A label marks a source about something else, such as an exception. A source marked secondary is not the state’s own record.

• “The Base Code is IECC 2021 with MA amendments: 780 CMR Chapter 11R (residential) and 780 CMR Chapter 13 (commercial).”

• “The tenth edition building code became first effective on October 11, 2024”

  “The tenth edition code is based on modified versions of the following 2021 International Codes (I-Codes)”

• About an exception

  “develop and promulgate, in consultation with the state board of building regulations and standards”

  “a municipal opt-in specialized stretch energy code”

• About an exception

  “The opt-in Stretch Code is IECC 2021 with key MA amendments: 225 CMR Chapter 22 (residential) and 225 CMR Chapter 23 (commercial).”

• About an exception

  “not more than ten cities and towns may adopt and amend general or zoning ordinances or by-laws”

Tracker cross-checks

Code adoption trackers are a cross-check. They are not Massachusetts’s own record.

• DOE’s energycodes.govCross-checkAgrees with the record

  Residential: 2021 IECC, effective 10/11/2024, mandatory statewide, state amendments yes

  energycodes.gov (opens in a new tab)Read Oct 17, 2026

Related pages

• See Massachusetts’s IECC residential on the map
• IECC residential adoption in every state
• All six codes in Massachusetts

Other codes in Massachusetts

• NEC2026 NECVerified
• IBC2021 IBCVerified
• IRC2021 IRCVerified
• IFCAnother model codeVerified
• IECC commercial2021 IECCVerified