# International Residential Code > The 2009 International Residential Code, incorporated by reference into the Maryland Building Performance Standards (COMAR 09.12.51), effective January 1, 2010. - Canonical: https://harth.build/resources/building-codes/us-states/maryland/irc-2009/ - Last updated: 2026-06-25 ## Direct answer and reference scope International Residential Code is presented here as a reference within the IRC 2009 collection for Maryland. The 2009 International Residential Code, incorporated by reference into the Maryland Building Performance Standards (COMAR 09.12.51), effective January 1, 2010. Use the [Maryland Building Codes Administration](https://labor.maryland.gov/labor/build/buildstatecodes.shtml) to confirm the code edition currently adopted for the project, and compare the model text with state amendments, local amendments, effective dates and the permit authority's interpretation. The [ICC code library](https://codes.iccsafe.org/codes) is the model-code publication path. This Harth page is a searchable reference transcription, not an official code publication, legal opinion or confirmation that this edition controls a particular address. Record the project jurisdiction, application date, occupancy, construction type and amendment set before relying on a section. Where this page conflicts with an official publication or the authority having jurisdiction, the official source controls. _Authored and prepared by Harth. Review scope: official verification path added; code text and current local applicability have not been independently reviewed._ Maryland's 2010 Building Performance Standards incorporated the 2009 IRC by reference, effective January 1, 2010, for one- and two-family dwellings. It covers the design and construction of one- and two-family dwellings and townhouses, covering building planning, structural, mechanical, plumbing, and energy provisions for homes. The full text below is reproduced from the 2009 edition as adopted into law, sourced from public.resource.org. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/agent?context=%2Fresources%2Fbuilding-codes%2Fus-states%2Fmaryland%2Firc-2009%2F - View this page in a browser: https://harth.build/resources/building-codes/us-states/maryland/irc-2009/ - All resources for agents: https://harth.build/llms.txt