Plumber

Before applying or renewing online…

make sure you meet all of the requirements
  • The fee is $151.90.
  • You must not have any outstanding, unpaid infractions with L&I.


  • Washington State only reciprocates with the state of Idaho. If applying for a reciprocal license, please mail or email a copy of your active Idaho journey level card or apprenticeship card as well as your driver's license to the department.

    Email: Plumbers@Lni.wa.gov

    Phone: 360-902-5207

  • Note: Out-of-state plumbers applying for the Washington plumber exam must contact the Plumber Certification office before submitting applications. If you are applying for a Washington plumbing license with an out-of-state certification and do not qualify for the Idaho reciprocal, please mail or email a copy of your active out-of-state plumbing license as well as your driver's license to the department
  • Email: Plumbers@Lni.wa.gov

    Phone: 360-902-5207

  • If applying for an examination as a plumber trainee of Washington, verify that all of your hours are on file with the department. You can verify your hours by calling our office at 360-902-5207 or emailing us at Plumbers@Lni.wa.gov:

    Department of Labor & Industries
    Plumber Certification Section
    PO Box 44470
    Olympia, WA 98504-4470

Before you apply online, you will need the following:
    • Your Social Security number.
    • Payment, we accept Visa, MasterCard, Discover and American Express credit cards.

      Visa Card

      Mastercard

      Discover

      American Express

      Visa

      MasterCard

      Discover

      American Express

    • Note: We also accept E-Check, a one time withdrawal from your checking account.
What L&I will do:
  • Process affidavits of experience.
  • Verify reciprocal Information.
  • Verify out-of-state license information.
  • Mail an examination notice if application is accepted.
  • Mail a notice requesting additional licensing fee once reciprocal is approved.
  • Send a letter if the application or reciprocal is denied, stating the reason for denial.
  • 16 hours of continuing education is required for renewal of jouney level or residential specialty plumber certificates. These 16 hours must consist of a minimum of 8 hours code and a minimum of 4 hours IRE and the other 4 hours may be from any category (code, IRE, IRP).
  • If you pay by your expiration date for your residential or Journey Level Plumbers certificate, your renewal fee is $121.60.
  • If you are renewing your residential or Journey Level Plumbers certificate after your expiration date and you have yet to pay the initial fee of $121.60 and your renewal is not past it's 90 day, your renewal fee is $243.20.
  • If you pay by your expiration date for your Backflow Plumbers certificate the renewal fee is $83.90.
  • If you are renewing your Backflow Plumbers certificate after your expiration date and your renewal is not more than 90 days late, your renewal fee is $167.80.
  • If your renewal is more than 90 days late, you may not renew and must contact us about retaking your certification exam.
  • If your certificate is suspended for any reason, you may not renew online and you must contact us about reinstating it.
  • You must not have any outstanding, unpaid infractions with L&I or a collection agency.
  • Renewal consists of paying the renewal fee and completing the required education. If not completed by your expiration date, late fees or retesting shall apply.
  • After you have renewed your certificate, check online by going to our Verify application and look yourself up to make sure your license is reflecting the new expiration date.
Before you renew online, you will need the following:
  • Your 12-digit license (certification) number.
  • Your Social Security Number
  • An active license (not suspended or canceled).
  • Payment, we accept Visa, MasterCard, Discover and American Express credit cards.

    Visa Card

    Mastercard

    Discover

    American Express

    Visa

    MasterCard

    Discover

    American Express

  • Note: We also accept E-Check, a one-time withdrawal from your checking account.

Renew your plumber or reciprocal certificate

About becoming a plumber

You must have a valid plumber certificate to work in the plumbing construction trade in Washington State.

The plumbing trade includes all:

  • Potable water building supply and distribution pipes,
  • Plumbing fixtures and traps,
  • Drainage and vent pipes,
  • Accessories (appurtenances) within the property lines of the premises,
  • Medical gas and medical vacuum systems, and
  • Water heaters.
Except for domestic pump and pump and irrigation systems, certification is not required to install plumbing systems outside of a building.

What is required to become a journey level or specialty plumber?

To become a certified journey level or specialty plumber in Washington, you must begin as a plumber trainee or submit a comparable license from another state or equivalent experience in the US military for consideration.

Expand or collapse group.

  • Expand/collapse Journey level plumber (PL01) — is qualified to work in all phases of plumbing construction.
    • 4 years or more (at least 8,000 hours) working as a plumber trainee under the supervision of a certified journey level plumber.
      Note: 2 years or more (at least 4,000 hours) must be spent working in commercial or industrial installations.

    Specialty plumber includes the following specialties:

  • Expand/collapse Residential (PL02) – is limited to installation, maintenance, and repair of plumbing in single family dwellings, duplexes, and apartment buildings which do not exceed three stories.
    • 3 years or more (at least 6,000 hours) working in the specialty under supervision of a certified residential or journey level plumber.
  • Expand/collapse Pump and irrigation (PL03) – is limited to installation, maintenance, and repair of equipment that is used to acquire treat, store, or move water suitable for drinking or irrigation purposes.
    • 2 years or more (at least 4,000 hours) working in the specialty under supervision of an appropriate certified plumber (excluding PL03A and PL30).
    • Working in this trade also requires electrical certification. See the steps to obtain a combination plumber/electrical certification.
  • Expand/collapse Domestic well (PL03A) – is limited to installation, maintenance, and repair of equipment that is used to acquire, treat, store, or move drinking or irrigationj water using a pump not exceeding 100 gallons per minute or 7.5 horsepower, single phase.
    • 1 year or more (at least 2,000 hours) working in the specialty under supervision of a certified plumber, (excluding PL30).
    • Working in this trade also requires electrical certification. See steps to obtain a combination plumber/electrical certification.
  • Expand/collapse Backflow (PL30) – is limited to maintenance and repair of existing backflow prevention assemblies within a building. This does not include installing or replacing backflow prevention assemblies.
  • An active BAT (Backflow Assembly Tester Certification) issued by the Washington State Department of Health is required.


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