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Plumbing careers
How to become a plumber in Washington
The license steps in Washington, from apprentice to master or contractor, taken from the official licensing pages – plus pay, apprenticeships and where to apply.
The short answer
In Washington you work as a certified plumber trainee under a certified plumber, log at least 8,000 hours over four or more years (4,000 of them commercial or industrial) and pass the L&I written exam to become a Journey Level Plumber; there is no master license, and certificates renew every three years with 24 CE hours.
The steps in Washington
- 1
Start as an apprentice
Plumber trainees and apprentices may work only under the supervision of a certified journey level or specialty plumber and must hold a plumbing training certificate from L&I.
- 2
Earn your journeyman (first independent) license
A Journey Level Plumber (PL01) needs at least four years (8,000 hours) as a supervised trainee, including at least 4,000 hours of commercial or industrial work, and must pass the state written exam.
- 3
Master or contractor license
We could not confirm the master or contractor requirements for Washington on an official page. Ask the licensing office for the current rule.
- 4
Keep your license current
Plumber certificates renew every three years on or before the holder's birthday, and renewal requires 24 hours of approved continuing education, including four hours on electrical safety.
Who licenses plumbers in Washington
Washington State Department of Labor & Industries (L&I), Plumber Certification Program. License types we found: Journey Level Plumber (PL01), Residential Plumber (PL02), Residential Service Plumber (PL04), Pump and Irrigation (PL03), Domestic Well (PL03A), Backflow (PL30), Medical Gas Piping Installer endorsement (MG01), Plumber Trainee, Plumbing Contractor.
Already licensed? Anyone can check a license on lni.wa.gov.
Licensed in another state?
Washington has reciprocal certification with Idaho for journey level plumbers; other out-of-state plumbers can present a comparable license or equivalent military experience for consideration.
Finding an apprenticeship
Most plumbers learn the trade through a 4- or 5-year apprenticeship, with about 2,000 hours of paid on-the-job training each year plus classroom instruction, according to the Bureau of Labor Statistics. The U.S. Department of Labor’s Registered Apprenticeships are paid jobs with progressive wage increases, classroom instruction and a portable, nationally recognized credential; programs are approved by the Department of Labor or a State Apprenticeship Agency. Search programs at apprenticeship.gov, or ask local plumbing contractors and union locals.
Pay and job outlook
$63,800
Median yearly pay for plumbers, pipefitters and steamfitters, May 2025 (BLS).
7%
Projected job growth from 2025 to 2035, with about 42,000 openings a year (BLS).
4-5 years
Typical apprenticeship, with about 2,000 hours of paid on-the-job training a year (BLS).
National figures from the BLS Occupational Outlook Handbook; pay varies by state and city.
Already a plumber in Washington?
57 plumbing businesses are listed on Plumbers Pages so far. Add your business free, or see plumbers in Washington.
Sources
Requirements come from Washington’s official licensing pages and statutes, checked October 2026. Rules change – confirm with the licensing office before you apply.
- app.leg.wa.gov/RCW/default.aspx?cite=18.106.070
- lni.wa.gov/licensing-permits/plumbing/plumber-certification/
- app.leg.wa.gov/RCW/default.aspx?cite=18.106.020
- app.leg.wa.gov/RCW/default.aspx?cite=18.106&full=true
- app.leg.wa.gov/RCW/default.aspx?cite=18.106.400
- lni.wa.gov/licensing-permits/contractors/hiring-a-contractor/verify-cont
- U.S. Bureau of Labor Statistics – Plumbers, pipefitters and steamfitters
- U.S. Department of Labor – Apprenticeship.gov for career seekers
General information, not legal advice. All states · How we write our guides