Mechanical code in Maryland

Maryland has adopted 2021 IMC (with 2021 IRC mechanical provisions) (IMC (ICC)). The adopting authority is Maryland Board of HVACR Contractors (Maryland Department of Labor). Verified June 28, 2026.

Adopts the 2021 International Mechanical Code with Maryland amendments under COMAR 09.15.05 (Compliance with the International Mechanical Code), administered by the Maryland Board of HVACR Contractors; the 2021 IRC mechanical provisions also apply to one- and two-family dwellings. Local jurisdictions may add amendments. A single discrete statewide effective date is not independently confirmed against a primary source.

It is the specific edition of a model code (for example the 2023 NEC, the 2021 IBC, or CSA C22.1:24) that a state or province has legally adopted and currently enforces. Codes are republished on roughly three-year cycles, and each jurisdiction adopts a new edition on its own schedule — often with amendments — so the edition in force varies by place and by discipline.

Not always. Many jurisdictions set a statewide or provincial baseline edition, but local building departments (the authority having jurisdiction, or AHJ) can amend it or enforce a different edition. Some states leave most adoption to local jurisdictions, and a few large cities such as Chicago and New York City run their own codes. Always confirm with your AHJ.

In the United States: the NEC (NFPA 70) for electrical, the ICC I-Codes (IBC/IRC) for building, the UPC (IAPMO) or IPC (ICC) for plumbing, the IMC/UMC for mechanical, the IFGC/NFPA 54 for fuel gas, and the IFC/NFPA 1 for fire. In Canada: the Canadian Electrical Code (CSA C22.1), the National Building, Plumbing and Fire Codes of Canada and their provincial editions, and CSA B149.1 for gas.

NFPA offers free read-only online access to many of its standards including the NEC, and the ICC publishes its I-Codes through a free online reading room. Canadian codes are typically published by CSA Group or the National Research Council and may require purchase or membership. Each result links to the official source.

Trade codes are copyrighted by their standards bodies (NFPA, ICC, IAPMO, CSA). This directory publishes only factual adoption data — which edition is in force, when it took effect, who the authority is, whether it is amended, and where to read it officially — and links you to the official source for the code text itself.