Mechanical Code

See also: Mechanical InspectionsMechanical Permit

The 2021 Washington state codes will be mandatory on March 15, 2024. The effective date for the 2021 Seattle codes is no sooner than July 1, 2024. Applicants may use the 2021 Washington codes with the draft Seattle amendments before March 15, 2024, when accompanied by a code modification request. Between March 15, 2024, and the Seattle code effective date, applicants may use either the 2018 or 2021 Seattle codes without a code modification request. Please visit the 2021 Seattle Code Adoption webpage for updates.

What Is It?

The Seattle Mechanical Code regulates design and installation of mechanical systems, appliances, appliance venting, duct and ventilation systems, combustion air provisions, hydronic systems, and solar systems. Seattle has adopted the 2018 International Mechanical Code, with amendments specific to our jurisdiction.

What It Isn't

This code does not cover regulations for fuel gas appliances and systems. Fuel gas includes natural, liquid petroleum, and manufactured gases. Those appliances and systems are regulated by the Seattle Fuel Gas Code.

Read the Code

This is a read-only version of the 2018 Seattle Mechanical Code. You can buy a full pdf version from iccsafe.org. Print copies are available for sale through the Seattle Services Portal. See our pricelist and our ordering instructions.

The 2018 Seattle Mechanical Code contains substantial copyrighted material from the 2018 International Mechanical Code which is proprietary to and copyrighted by International Code Council, Inc. The licensed material is copyrighted by the International Code Council, Inc., has been obtained and reproduced with permission. The acronym “ICC” and the ICC logo are trademarks and service marks of ICC. ALL RIGHTS RESERVED.

This is a read-only version of the 2015 Seattle Mechanical Code. You can buy a full version from iccsafe.org.

The 2015 Seattle Mechanical Code contains substantial copyrighted material from the 2015 International Mechanical Code which is proprietary to and copyrighted by International Code Council, Inc. The licensed material is copyrighted by the International Code Council, Inc., has been obtained and reproduced with permission. The acronym “ICC” and the ICC logo are trademarks and service marks of ICC. ALL RIGHTS RESERVED.

Proposed Changes

We are updating the Seattle construction codes to the 2021 editions. See the 2021 Seattle Code Adoption page for more information.

Construction and Inspections

Nathan Torgelson, Director
Address: 700 5th Ave, Suite 2000, Seattle, WA, 98104
Mailing Address: P.O. Box 34019, Seattle, WA, 98124-4019
Phone: (206) 684-8600
Phone Alt: Violation Complaint Line: (206) 615-0808
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SDCI issues land use, construction, and trade permits, conducts construction and housing-related inspections, ensures compliance with our codes, and regulates rental rules. SDCI is committed to an antiracist workplace and to addressing racism through our work in the community.