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    Plumbing Code Adoption

    Washington Plumbing Code: Uniform Plumbing Code (Washington amendments) 2021

    Washington follows Uniform Plumbing Code (Washington amendments) 2021 as the basis for plumbing work. Permits and inspections are issued by the local Authority Having Jurisdiction (AHJ), which may publish additional amendments.

    Adoption details

    Model code family
    IPC / UPC
    Adopted edition
    Uniform Plumbing Code (Washington amendments) 2021
    Last verified
    2026-05-29

    Related resources for Washington

    Frequently Asked Questions

    What plumbing code does Washington use?

    Washington currently follows Uniform Plumbing Code (Washington amendments) 2021 for plumbing work. Always confirm the in-force edition with the local Authority Having Jurisdiction (AHJ) — county or city amendments can apply.

    Do I need a permit for plumbing work in Washington?

    Most plumbing work in Washington — including new installations, system replacement, and gas-fueled appliance hookups — requires a permit from the local building department and an inspection at completion. Homeowner permits are typically allowed for owner-occupied residences; commercial work requires a licensed contractor.

    Where do I check Washington plumbing code amendments?

    Local jurisdictions (city or county) often publish amendments on the state's building-codes board website or in the municipal code. The current Uniform Plumbing Code (Washington amendments) 2021 text is published by its model-code body (ICC, IAPMO, or NFPA depending on the trade).

    Reference guidance only — adoption editions and local amendments vary by city or county. Always confirm requirements with your local Authority Having Jurisdiction (AHJ) before designing, permitting, or constructing.

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