Washington Plumbing Legislation, Codes, and Guidelines

Plumbing Codes and Legislation in Washington State

The state of Washington regulates plumbing systems through the adoption of the 2021 Uniform Plumbing Code (UPC), which is published by the International Association of Plumbing and Mechanical Officials (IAPMO). This model code is adopted by reference and modified by state-specific amendments to create the Washington State Plumbing Code, codified under Chapter 51-56 of the Washington Administrative Code (WAC). These regulations are established under the authority of the Revised Code of Washington (RCW) Chapter 19.27, which governs the State Building Code.

Primary State Agencies

Two primary state entities oversee the plumbing regulatory framework in Washington:

Washington State Building Code Council (SBCC): This council is responsible for the adoption, maintenance, and amendment of the state building codes, including the Washington State Plumbing Code. They regularly review and update these codes to ensure they remain consistent with state safety and health standards.
Washington State Department of Labor & Industries (L&I): This department is the primary authority for the administration of plumber certification, plumbing contractor licensing, and enforcement of professional standards. While the SBCC sets the technical code, L&I manages the workforce and business regulations associated with the plumbing trade, as outlined in RCW Chapter 18.106 and WAC Chapter 296-400A.

It is important to note that while the state sets the minimum standards, local jurisdictions (cities and counties) are responsible for issuing permits and conducting inspections. Local authorities may also adopt additional, stricter amendments to the state code.

Washington Plumbing Legislation, Codes, and Guidelines

Plumbing Codes and Legislation in Washington State

Primary State Agencies

Resources to Learn More

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