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How to become a plumber in Washington

To work as a plumber in Washington, you need your own certificate of competency from the Washington State Department of Labor & Industries (L&I). The certificate of competency belongs to you and not to your employer, so you keep it when you change jobs.

See your steps Find an apprenticeship

Your ladder

Dates if you start in Nov 2026 and work 40 hours a week.

  1. ApprenticeStart here
  2. Journey level plumber (PL01) certificate of competency8,000 hours on the job
  3. Plumbing contractor licenseRun your own business

First: start as an apprentice.

Find an apprenticeship

Dates are estimates, worked out from the hours on the job each license requires and the hours a week you pick.

Your steps

If you have no experience, you can start with a job as a plumber trainee. As a trainee, you get paid while you build your hours. Once you complete your hours, you can take the exam.

To qualify for the journey level plumber (PL01) certificate of competency, you need 8,000 hours on the job. If you work full time, you reach 8,000 hours in about 4 years.

Steps for: New to the trade. The dates follow your ladder. Change where you are, your start month or your hours a week at the top of the page.

  1. Step 1, Start here

    Start as an apprentice

    An apprenticeship is a paid job with training. You work for an employer and you learn the trade on the job. You can compare 7 registered plumber apprenticeship programs in Washington by what they pay. Pay on day one runs from $15.68 to $36.36 an hour, and the journey rate (the hourly pay of a fully qualified worker) runs from $33.73 to $77.21 an hour.

    The programs that pay the most at completion

    See all 7 programs

  2. Step 2,

    Get hired as a plumber trainee

    Find a job as a plumber trainee with a plumbing contractor, or start in a registered apprenticeship (a paid job with training). You get paid while you build your hours, and your hours count either way.

  3. Step 3, From day one

    Record your hours

    Keep your own record of your hours from your first day. Your hours count only when you work as a trainee under a certified plumber.

  4. Step 4,

    Complete your hours

    To qualify for the journey level plumber (PL01) certificate of competency, you need 8,000 hours on the job. The other certificates of competency require 6,000 hours or 4,000 hours.

  5. Step 5,

    Take your classroom hours

    Before the journey level exam, you need 16 classroom hours.

  6. Step 6,

    Take the exam

    L&I charges $202.10 for the exam, and the testing company charges its own fee.

  7. Step 7,

    Pay for your certificate of competency

    Once you pass the exam, L&I sends you an invoice for your certificate of competency. The journey level plumber (PL01) certificate of competency costs $242.70.

Other plumber licenses

If your certificate of competency requires 16 classroom hours, you take the hours before the exam. At least 4 of the hours must cover electrical work.

Journey level plumber (PL01) certificate of competency

Hours on the job
8,000
Exam
$202.1

The journey level plumber (PL01) certificate of competency requires 8,000 hours on the job as a plumber trainee under a certified journey level plumber. You also need 16 classroom hours, and you must pass the exam for this certificate of competency.

The certificate of competency costs $242.70, and L&I sends you the invoice once you pass the exam.

You renew the journey level plumber (PL01) certificate of competency every 3 years. The renewal costs $242.70. You need 24 hours of continuing education to renew.

Of the 8,000 hours, 4,000 must be commercial plumbing under direct supervision.

Up to half of your hours can come from a training school.

Residential (PL02) specialty plumber certificate of competency

Hours on the job
6,000
Exam
$202.1

The residential (PL02) specialty plumber certificate of competency requires 6,000 hours on the job in the specialty, under a certified residential plumber or a certified journey level plumber. You also need 16 classroom hours, and you must pass the exam for this certificate of competency.

The certificate of competency costs $242.70, and L&I sends you the invoice once you pass the exam.

You renew the residential (PL02) specialty plumber certificate of competency every 3 years. The renewal costs $242.70. You need 24 hours of continuing education to renew.

Residential service (PL04) plumber certificate of competency

Hours on the job
4,000
Exam
$202.1

The residential service (PL04) plumber certificate of competency requires 4,000 hours on the job as a plumber trainee under a certified plumber. You must also pass the exam for this certificate of competency.

The certificate of competency costs $242.70, and L&I sends you the invoice once you pass the exam.

You renew the residential service (PL04) plumber certificate of competency every 3 years. The renewal costs $242.70. You need 24 hours of continuing education to renew.

You must work your first 2,000 hours under a journey level plumber or a residential specialty plumber. You can work your other 2,000 hours under a residential service plumber.

Pump and irrigation (PL03) specialty plumber certificate of competency

Hours on the job
4,000
Exam
$202.1

The pump and irrigation (PL03) specialty plumber certificate of competency requires 4,000 hours on the job. You also need 16 classroom hours, and you must pass the exam for this certificate of competency. To work in this specialty, you also need an electrical certificate.

The certificate of competency costs $242.80, and L&I sends you the invoice once you pass the exam.

You renew the pump and irrigation (PL03) specialty plumber certificate of competency every 3 years. The renewal costs $242.80. You need 24 hours of continuing education to renew.

To run a plumbing business

Plumbing contractor license

To get the plumbing contractor license, the business must employ a full-time plumber who holds a certificate of competency. The plumber must hold the journey level plumber (PL01) certificate of competency or a specialty certificate of competency that covers the work the business does. This license allows you to run your own plumbing business.

The plumbing contractor license costs $148.10.

You renew the plumbing contractor license every 2 years. The renewal costs $148.10.

Take the exam

LicenseExam
Journey level plumber (PL01) certificate of competencyWashington state plumbers' competency examination, journey level
Residential (PL02) specialty plumber certificate of competencyResidential specialty plumber examination
Residential service (PL04) plumber certificate of competencyResidential service plumbing examination
Pump and irrigation (PL03) specialty plumber certificate of competencyDomestic pump specialty plumbers examination

Each of the 4 certificates of competency has its own exam. L&I charges $202.10 for the exam.

The testing company that gives the exam also charges its own fee. Ask L&I which company gives your exam and what it charges.

Use the official name of your exam when you contact L&I.

What plumbers earn in Washington

$38.96an hour

$81,030 a year, full time

Half of the plumbers on a payroll in Washington earn more than $38.96 an hour, and half earn less. The federal wage survey puts the yearly figure at $81,030.

These figures cover everyone on a payroll as a plumber in Washington, from apprentices to people with decades in the trade, so they aren't a starting wage. The survey counts 12,470 jobs. The figures don't include self-employed plumbers.

The yearly figure is for full-time work all year, which is 2,080 hours.

Use a license from another state

If you hold a plumber license from another state, check whether L&I recognizes it. L&I recognizes a license from this state.

Washington licenseRecognized from
Journey level plumber (PL01) certificate of competencyIdaho

If your license is from any other state, you can ask L&I to consider a comparable license or equivalent experience in the U.S. military. Contact L&I before you move.

If you move from Washington to another state, ask the office that issues plumber licenses in that state whether it recognizes your certificate of competency.

Questions

How long does it take to become a plumber in Washington?

If you work full time, you reach the 8,000 hours for the journey level plumber (PL01) certificate of competency in about 4 years. You reach 6,000 hours in about 3 years and 4,000 hours in about 2 years.

Can you become a plumber with no experience?

Yes. You can start as a plumber trainee or in a registered apprenticeship, and you learn the trade on the job. Ask your employer who will confirm your hours.

How much does a plumber certificate of competency cost in Washington?

L&I charges $202.10 for the exam, and the testing company charges its own fee. Once you pass the exam, the journey level plumber (PL01) certificate of competency costs $242.70.

Contact the licensing office

Washington State Department of Labor & Industrieslni.wa.gov/licensing-permits/plumbing/plumber-certification/index

Words to know

Apprentice
Someone who learns the trade on the job, working under a licensed worker.
Journeyman
The license level after apprentice. Some states write journeyperson, journeyworker or journey level.
Continuing education
Classes you take to keep your license.
Reciprocity
An agreement that lets you use a license from one state to get a license in another.
Median
The middle figure. Half of the workers earn more, and half earn less.

Sources

6
  1. The plumber certification page at the Washington State Department of Labor & Industries
  2. Revised Code of Washington 18.106.400, the plumbing contractor license rule
  3. The page on getting and renewing a plumber certification at the Washington State Department of Labor & Industries
  4. Occupational Employment and Wage Statistics, May 2025 state file
  5. Washington Administrative Code rule 296-400A-121, which sets the trainee experience and examination requirements for plumbers
  6. Washington Administrative Code rule 296-400A-045, the fees for plumber certification and exam applications

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