Washington Plumbing License Requirements
Yes. Washington licenses plumbers through the Washington L&I, Plumber Certification. It issues apprentice, journeyman and contractor credentials.
State plumber license · By BrazeJobs Team · Updated
License tiers
| Apprentice | Plumber trainee certificate |
| Journeyman | Journey Level (PL01); Residential Specialty; Residential Service |
| Master | No state license |
| Contractor | L&I contractor registration |
Requirements
| Journeyman experience | PL01: 8,000 over 4 years (4,000 commercial/industrial); Residential: 6,000; Service: 4,000 |
| Exam | L&I exam |
| Continuing education | 24 hours (min 12 UPC) |
| Local license | No (state license covers) |
| Board | Washington L&I, Plumber Certification |
Apprenticeship
| Registering agency | State Apprenticeship Agency (Washington L&I) |
- Source: apprenticeship.gov · checked November 6, 2026
- Source: lni.wa.gov · checked November 6, 2026
Plumbing code
| Code in force | 2021 UPC with state amendments |
State Building Code adopted by SBCC, effective March 15, 2024, with state amendments.
- Source: app.leg.wa.gov · checked November 5, 2026