Washington state has adopted the 2018 edition of the Uniform Plumbing Code, however Seattle has its own plumbing code created by the SDCI (Seattle Department of Construction & Inspections) at Seattle.gov that differs from the state wide plumbing codes in some ways, mostly with additional restrictions for safety during repairs, and standards for fixtures. If you'd like to learn more about the nuances of Seattle's plumbing code, our page "Top 5 Plumbing Questions You Should Be Asking!" has a few topics that we recommend homeowners be aware of if they own or are hoping to own a home in King County.