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Plumbing in King County, Washington

Browse 261 verified plumbing registered across King County, Washington (including Seattle, Bellevue, Kent, Renton, Federal Way, Kirkland). Every record is compiled from Washington State Department of Labor & Industries (WA L&I) public credential files under Revised Code of Washington RCW 18.27 (Contractor Registration), RCW 19.28 (Electrical EL01–EL06), and RCW 18.106 (Plumbing PL01/PL02).

Official State Authority: Washington State Department of Labor & Industries (WA L&I) Official Registry · County Seat: Seattle

Municipalities in King County (19)

Select a city or town in King County to view local permit guidance and registered plumbing records:

Seattle 73Kent 23Auburn 22Woodinville 15Kirkland 14Renton 14Bellevue 12Burien 12Redmond 9Tukwila 9Federal Way 8Maple Valley 8Shoreline 8North Bend 6Enumclaw 4Black Diamond 3Covington 3Kenmore 3Sammamish 3

261 plumbing records · King County, WA

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Public Directory Quality: Official WA L&I license records across King County · Zero sponsored order · Never sold as a lead · How our data works →

Plumbing directory — King County

261 matching records across 19 open municipalities · 25 on this page · Contactable records first, then alphabetical.

Before the first call

  • Describe the job and ask whether it is within their scope and service area.
  • Check the credential with its issuing authority and ask what applies where the work will happen.
  • Ask about insurance, availability, who will do the work, and a written scope.
  • Ask about callout fees, labor or fixed rates, materials, cancellation and any estimate charge.
Prepare a project brief

Verification Overview & Key Takeaways: How to Check Official Credentials

HomeCrafto displays source records with different scopes, including licenses, registrations, municipal permits and community records. A source entry is not proof of qualification for your job. Before signing a work order or paying a deposit, homeowners should confirm that the contractor’s credential number is active, verify that the license classification covers the specific trade scope required for the job, and request a current Certificate of Insurance (COI) directly from the issuing insurance carrier. Independent verification protects your property and ensures compliance with local building codes.

How do you verify a contractor license number and insurance on official portals (FAQ)?

You can verify active license standing and consumer protection rules directly through official government portals, including Washington L&I Contractor Verify, the California Contractors State License Board (CSLB), the Connecticut eLicense Portal, USA.gov State Consumer Protection Offices, and FTC Home Improvement Consumer Guidance. Always confirm municipal permit requirements with your local building department before work begins.