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Washington HVAC Legislation, Codes, and Guidelines

Washington State HVAC Building Codes and Legislation

The Washington State Building Code is established by the state legislature under the Revised Code of Washington (RCW) Chapter 19.27. This statute mandates the adoption of specific national model codes, which are then amended at the state level to meet Washington's unique requirements for safety, energy efficiency, and indoor air quality.

As of the current standards, Washington utilizes the 2021 editions of the International Code Council (ICC) model codes, including the 2021 International Mechanical Code (IMC) and the 2021 International Residential Code (IRC). Additionally, Washington maintains its own state-specific energy and ventilation standards, known as the Washington State Energy Code (WSEC) and the Washington State Ventilation and Indoor Air Quality Code, which are codified in Title 51 of the Washington Administrative Code (WAC).

The primary agency responsible for the development, adoption, and amendment of these codes is the Washington State Building Code Council (SBCC). The SBCC is a governor-appointed body that advises the legislature on building code issues and ensures that the state's construction standards remain consistent and effective across all local jurisdictions. While the state sets these minimum requirements, local cities and counties are responsible for the enforcement of these codes and may adopt local amendments, provided they are not less restrictive than the state-level standards and, in many cases, receive approval from the SBCC.

Resources to Learn More

Select a County Below to Learn More About That Jurisdiction in Washington

Permit rules operate within the above structure but can be nuanced at the county or municipal level. Select your local area below for specific ordinances, local codes, and direct links for your locality Building Department.