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Washington Plumbing Licenses & Certifications

The Plumber Advisory Board is a Board under the Washington State Department of Labor & Industries in charge of the Plumber Certification Program. The plumber certification program certifies plumbing professionals and ensures that their work meets State requirements. For further information on the State dispositions for plumbing work, refer to Chapter 18.106 of the Revised Code of Washington.

Plumbing Licenses & Certifications

  • Backflow (PL30)
  • Domestic Well (PL03A)
  • Journey Level Plumber (PL01)
  • Medical Gas Piping Installer (MG01)
  • Pump and Irrigation (PL03)
  • Residential (PL02)
  • Residential Service (PL04)

How to Get a Plumbing License or Certification in Washington?

  1. Have experience as a Plumber Trainee. If you don’t have experience as a Plumber Trainee, meet the following requirements and apply for a Plumbing Trainee certificate:
    • Be at least 16 years of age
    • Work under the supervision of a journey level or certified plumber
    • Take 8 hours of plumbing code and 4 hours of electrical classes in two years
  2. Fill out anAffidavit of Experience to report the supervised work hours as a plumber trainee
  3. Meet the required experience or education depending on the license applying for:
    • Journey Level Plumber (PL01): 8,000 hours as a plumber trainee and 4,000 hours working in commercial/ industrial installations
    • Medical Gas Piping Installer (MG01): Complete a minimum of 32 hours of training in a medical gas training course
    • Residential (PL02): 6,000 hours of experience under the supervision of a Residential or Journey Level plumber
    • Residential Service (PL04): 4,000 hours as a plumber trainee under the supervision of a Journey Level, Residential or Residential Service plumber
    • Pump and Irrigation (PL03): 4,000 hours working under the supervision of a certified plumber, except a Pump and Irrigation (PL30) or a Domestic Well (PL03A) plumber
    • Domestic Well (PL03A): 2,000 hours under the supervision of a certified plumber, except a Pump and Irrigation Plumber (PL30)
    • Backflow (PL30): Have an active Backflow Assembly Tester Certification issued by the Washington State Department of Health
  4. Fill out and notarize an Application for Contractor License or a Combination Contractor Application if applying for the Pump and irrigation (PL03) and the Domestic well (PL03A) licenses
  5. Complete and obtain a Surety Bond or Assigned Savings Account
  6. Get a Certificate of Liability Insurance
  7. Choose a designated plumber to hold the valid plumber certificate. The designated plumber can be another person or the applicant, depending on whether they are applying as a business or as a sole proprietor
  8. Satisfy the following educational requirements and apply for the plumber examination with PSI©:
    • Journey Level Plumber (PL01), Residential (PL02), and Residential Service (PL04) plumbers - 24 hours of continuing education, including:
      • 12 hours of Uniform Plumbing Code
      • 4 hours of Industry-Related Electrical
      • 8 hours in any Code, Industry-Related Electrical, or Industry-Related Plumbing area
    • Pump and Irrigation (PL03) and Domestic Well (PL03A) plumbers:
      • 24 hours of combination classes that cover plumbing and electrical subjects, or
      • 12 hours of plumbing and 12 hours of electrical education
    • Backflow (PL30) plumbers - No educational requirements; only a copy of an active Backflow Assembly Tester card is needed
    • Medical Gas Piping Installers (MG01) - A notarized Affidavit of Continuity to report applicable brazing experience. brazing experience must be certified every 6 months
  9. Refer to PSI© Plumbing Examinations Candidate Information Bulletin. For more information on the test (locations, subjects, books to prepare for the exam)
  10. Submit a complete packet with all the required documents to:
    Washington State Department of Labor & Industries
    Plumber Certification
    PO Box 44470
    Olympia WA 98504-4470

Important Links and Contact Information for Plumbing Licenses & Certifications

Useful Links for Plumbing Contractors in Washington

Contact Information for Plumbing Applicants

Plumber Certification Program

Washington State Department of Labor & Industries
Plumber Certification
PO Box 44470
Olympia WA 98504-4470
360-902-5207
This email address is being protected from spambots. You need JavaScript enabled to view it.

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