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Washington plumber license requirements
The answer
Washington certifies plumbers statewide through L&I. Journey-level requires a recognized course of study (armed services or accredited school) OR 4+ years under the direct supervision of a certified journey-level plumber, then the exam. Specialty plumbers need 3 years; residential service plumbers 2 years.Your paths to the license
4 years supervised to journey level
Register as a plumber trainee and work 4+ years under the direct supervision of a certified journey-level plumber, then pass the journey-level exam (RCW 18.106.040).
Accredited course of study
Completing a plumbing course of study in the U.S. armed services or at a school accredited by the Workforce Training and Education Coordinating Board qualifies you for the exam in place of the 4 supervised years.
Residential specialty first
The residential specialty needs 3 years supervised (residential service: 2 years) — a faster credential while you continue toward journey level.
Licensed in another state
No blanket reciprocity — L&I evaluates out-of-state supervised experience toward the 4-year requirement; you take the Washington exam.
License levels in Washington
| Level | What it takes | Fee |
|---|---|---|
| Plumber trainee | Register with L&I; work under supervision while accruing experience. | — |
| Residential service plumber | 2+ years supervised experience (or approved course of study) + exam. | — |
| Specialty plumber (residential) | 3+ years supervised experience in the specialty (or approved course) + exam. | — |
| Journey level plumber | 4+ years under direct supervision of a certified journey-level plumber (or armed-services/accredited course of study) + exam. | — |
Published fees
| Item | Amount |
|---|---|
| Exam / certificate / renewal | Set by L&I rule — see the current fee schedule on lni.wa.gov |
The exam
| Provider | L&I (via testing vendor) |
| Fees | Exam and certificate fees set by L&I rule — see the current fee schedule |
Moving here with a license? Renewal? The rest of the picture
Reciprocity: No formal reciprocity; supervised out-of-state experience is evaluated toward exam eligibility. Check your exact state pair →
Renewal & continuing education: Certificates renew on a multi-year cycle with continuing-education requirements set by rule — confirm your cycle on your certificate.
Watch out: Medical-gas and other endorsements have added requirements. · Plumbing contractor (business) licensing is separate from individual certification.
Official sources for this page
Washington plumber licensing FAQ
How many hours do you need to become a licensed plumber in Washington?
Washington certifies plumbers statewide through L&I. Journey-level requires a recognized course of study (armed services or accredited school) OR 4+ years under the direct supervision of a certified journey-level plumber, then the exam. Specialty plumbers need 3 years; residential service plumbers 2 years.
What does the Washington plumber license cost?
Exam and certificate fees set by L&I rule — see the current fee schedule. Fee amounts are published on the current official application — see the sources below.
Does Washington have plumber license reciprocity?
No formal reciprocity; supervised out-of-state experience is evaluated toward exam eligibility.
How often does the license renew?
Certificates renew on a multi-year cycle with continuing-education requirements set by rule — confirm your cycle on your certificate.
Get your personal route
Four questions — your experience and training matched against Washington's actual routes.