How to get a Journey level plumber (PL01) license in Washington

Washington plumber licenses

Washington issues 10 plumber credentials. Each has its own section below; the table shows what each one covers and its headline requirements.

Applies to every license level

These rules are the same for several of the Washington plumber licenses on this page, so they are shown once here, with the licenses they apply to. Each license's own section lists only what differs.

1. Every license level (all 10)

From another state

Military service members, veterans and spouses: A plumbing course of study in the U.S. armed services counts as evidence of experience; military members can show equivalent experience to L&I.⁴

2. Every license level except Plumbing contractor license

Requirements

Social Security number

Social Security number or individual taxpayer identification number required on applications.⁶

Also required

Must carry photo ID and wear the certificate visibly on the front of the upper body while working.²

3. Every license level except Temporary permit (out-of-state plumbers) and Backflow specialty plumber (PL30)

How to apply

Application form

Form (PDF, lni.wa.gov)⁶⁷⁸

4. Every license level except Temporary permit (out-of-state plumbers), Medical gas piping installer endorsement (MG01) and Plumbing contractor license

Fees

5. Every license level except Plumber trainee (PT00; backflow trainee PT31), Temporary permit (out-of-state plumbers) and Plumbing contractor license

Renewal

How often

Every 3 years²

6. Every license level except Plumber trainee (PT00; backflow trainee PT31), Temporary permit (out-of-state plumbers), Medical gas piping installer endorsement (MG01) and Plumbing contractor license

Fees

The board's pages we cite do not list the exam fee; check it with the exam provider, PSI³, when you schedule.

From another state

7. Every license level except Plumber trainee (PT00; backflow trainee PT31), Temporary permit (out-of-state plumbers), Backflow specialty plumber (PL30) and Medical gas piping installer endorsement (MG01)

Renewal

Renew online

lni.wa.gov⁹⁵

8. Journey level plumber (PL01), Temporary permit (out-of-state plumbers), Limited volume domestic pump specialty plumber (PL03A), Pump and irrigation specialty plumber (PL03) and Residential specialty plumber (PL02)

From another state

9. Journey level plumber (PL01), Limited volume domestic pump specialty plumber (PL03A), Pump and irrigation specialty plumber (PL03), Residential service plumber (PL04) and Residential specialty plumber (PL02)

Fees

How to apply

1. Work as a registered plumber trainee (PT00, $60/yr) under the required supervision, file notarized affidavits of experience each year and keep CE current.⁴ Form (PDF, lni.wa.gov)¹⁰
2. Complete 16 hours of CE (at least 4 electrical) before testing, then submit the exam application (F627-008-000) online or by mail with the $202.10 fee and a photo ID copy.² Form (PDF, lni.wa.gov)⁶
3. After L&I approval, schedule and pay PSI; pass the exam.³
4. Pay the certificate (1st card) fee within 90 days of passing.²

Renewal

When it expires

Certificate expires on the holder's birth date; renew no more than 90 days before expiry.²

Continuing education

At least 24 hours each renewal period²

If it expires

More than 90 days late: retake the exam. Inactive status (no work, no CE) can be requested before expiry; reinstatement within 5 years without exam.²

10. Backflow specialty plumber (PL30), Limited volume domestic pump specialty plumber (PL03A), Pump and irrigation specialty plumber (PL03), Residential service plumber (PL04) and Residential specialty plumber (PL02)

From another state

11. Journey level plumber (PL01), Backflow specialty plumber (PL30), Residential service plumber (PL04) and Residential specialty plumber (PL02)

Fees

12. Journey level plumber (PL01), Limited volume domestic pump specialty plumber (PL03A), Pump and irrigation specialty plumber (PL03) and Residential specialty plumber (PL02)

Requirements

Education or training

At least 16 clock hours²
16 hours of approved continuing education (at least 4 hours industry-related electrical) before testing; RCW requires at least 16 hours classroom training incl. electrical safety.²
Who may teach it: L&I-approved courses; approved apprenticeship/trade-school students may work unsupervised for the last six months with an endorsement ($43.30).²
Alternative: Training-school programs may supply no more than half of the required experience.²

How to apply

Temporary or provisional license

Out-of-state plumbers: one-time 120-day temporary permit.²

13. Journey level plumber (PL01), Residential service plumber (PL04) and Residential specialty plumber (PL02)

Fees

Renewal

Renewal fee

$242.70²

Required topics

At least 12 hours Uniform Plumbing Code and 4 hours industry-related electrical; remaining 8 hours any approved category.¹¹
Up to 4 of the 24 hours may be approved behavioral health and wellness training.¹

Approved courses

L&I-approved courses only; providers report rosters to L&I (up to 30 days).²

Late renewal

Late renewal fee: $485.40² (renewal within 90 days after expiry (doubled fee); after 90 days the exam must be retaken)
Reinstatement fee: $324.50² (return from inactive status (under 5 years))

14. Limited volume domestic pump specialty plumber (PL03A) and Pump and irrigation specialty plumber (PL03)

Requirements

Exam

Washington domestic pump / pump and irrigation specialty examination⁶
Given by: PSI³
When you can take it: L&I approves eligibility (affidavits of experience and CE on file); the approval letter explains how to schedule with PSI. Approved applications are good for one year.³
Retakes: After a failure, submit a new application and $202.10 fee; keep working under supervision with an active trainee card until you pass. No limit on attempts.³
Time limit: Pay the certificate fee within 90 days of passing or retest.²
Exam waived: Reciprocity (Idaho, journey level only) or advisory-board-approved national exam; otherwise all out-of-state plumbers take the Washington exam.³

Also required

Also requires a Washington electrical specialty certificate (combination license; separate electrical application).⁶

Fees

Each line is a separate charge as the board lists it. The board does not publish a combined total, so none is shown here.

Renewal

Renewal fee

$242.80²

Required topics

At least 12 of 24 hours in plumbing; the electrical program separately requires 24 hours (combination classes count for both).¹¹
Up to 4 hours behavioral health and wellness training may count.¹

Approved courses

L&I-approved courses only.²

Late renewal

Late renewal fee: $485.60² (renewal within 90 days after expiry (doubled fee); after 90 days the exam must be retaken)
Reinstatement fee: $486² (return from inactive status (under 5 years))

Who needs a Journey level plumber (PL01) license

All phases of plumbing on residential, commercial and industrial sites.²

Work that does not need this license:

• No certificate needed for plumbing at your own residence, farm or place of business, or on your own property; nor for farm plumbing.¹
• A business or plant doing plumbing on premises it owns or operates is exempt; householders may get unpaid help from friends/relatives not in the trade.¹
• Except for domestic pump and pump-and-irrigation systems, no certificate is needed for plumbing outside a building (e.g. water service and sewer connections).⁴
• Medical gas work has no exemptions.¹

Requirements for a Journey level plumber (PL01) license

More rules for this license are shared with other levels: group 1, group 2, group 3, group 4, group 5, group 6, group 7, group 8, group 9, group 11, group 12 and group 13 under Applies to every license level.

Experience

At least 8,000 hours of on-the-job training²
8,000 hours over at least four years as a trainee, including 4,000 hours of commercial plumbing under direct supervision of a certified journey level plumber.²
Supervision: Direct supervision of a certified journey level plumber.⁴
Substitute: Foreign journey level certificate (4-year training + exam) may earn up to 4,000 hours credit; another 4,000 commercial hours must be earned in Washington.²

Exam

Washington journey level plumber examination (2015 UPC with WA amendments, closed book)³
Given by: PSI³
When you can take it: L&I approves eligibility (affidavits of experience and CE on file); the approval letter explains how to schedule with PSI. Approved applications are good for one year.³
Retakes: After a failure, submit a new application and $202.10 fee; keep working under supervision with an active trainee card until you pass. No limit on attempts.³
Time limit: Pay the certificate fee within 90 days of passing or retest.²
Exam waived: Reciprocity (Idaho, journey level only) or advisory-board-approved national exam; otherwise all out-of-state plumbers take the Washington exam.³

Renewal and continuing education

Moving to Washington with a license from another state

These are the routes L&I publishes for the Journey level plumber (PL01) license. The other plumber licenses have their own routes in their sections below.

Plumber trainee

Learns plumbing under supervision of a certified plumber (75% on-site; ratios apply); hours count toward exam eligibility only while the card is active.²

Requirements

Minimum age

16 years old²

Experience

No prior experience; trainee must work under direct supervision (journey level ratio 1:1; residential up to 3:1 until Dec 31, 2028, then 2:1).²

Also required

Pump and irrigation / domestic pump trainees also need an electrical trainee card.¹²

Fees

Each line is a separate charge as the board lists it. The board does not publish a combined total, so none is shown here.

How to apply

1. Apply with form F627-003-000 by mail or at an L&I office with your SSN/ITIN and the $60 fee.¹² Form (PDF, lni.wa.gov)⁷
2. Work under supervision, log hours, and file notarized affidavits of experience within 30 days after each renewal date.¹²

Processing time

Certificate mailed within 2-4 weeks.¹²

Renewal

How often

Every year²

Renewal fee

$60¹²

Continuing education

At least 8 hours each renewal period²

Required topics

Over two years: at least 8 hours plumbing code and 4 hours industry-related electrical; other 4 hours any category.¹²

Exemptions

Registered apprentices getting equivalent classroom training meet CE; backflow trainees are exempt.²

If it expires

Without CE the card goes inactive and hours worked while expired/inactive are not credited.²

From another state

More rules for this license are shared with other levels: group 1, group 2, group 3 and group 4 under Applies to every license level.

Temporary permit

Lets an out-of-state plumber work at their current level while waiting to take the Washington exam; one-time, 120 days (four months), non-renewable.³

Requirements

Experience

Active state-issued journey level, domestic pump or residential specialty license; never took the Washington exam; not a trainee/apprentice; never held a temporary permit or WA certificate.³
License you must hold first: Current out-of-state plumber license.²

Fees

Each line is a separate charge as the board lists it. The board does not publish a combined total, so none is shown here.

How to apply

1. Submit your out-of-state license and photo ID for review, then apply on F627-008-000 paying the exam application and permit fees.³ Form (PDF, lni.wa.gov)⁶

Renewal

How often

Every 4 months²

More rules for this license are shared with other levels: group 1, group 2 and group 8 under Applies to every license level.

Backflow specialty plumber (PL30)

Maintenance and repair (cleaning, replacing internal parts) of backflow assemblies inside buildings; not installing or replacing assemblies.²

Requirements

Experience

No hours requirement; must hold an active Backflow Assembly Tester (BAT) certification from the Washington State Department of Health.²
License you must hold first: Active DOH Backflow Assembly Tester (BAT) certification.⁴

Exam

Washington backflow specialty examination⁶
Given by: PSI³
When you can take it: L&I approves eligibility (affidavits of experience and CE on file); the approval letter explains how to schedule with PSI. Approved applications are good for one year.³
Retakes: After a failure, submit a new application and $202.10 fee; keep working under supervision with an active trainee card until you pass. No limit on attempts.³
Time limit: Pay the certificate fee within 90 days of passing or retest.²
Exam waived: Reciprocity (Idaho, journey level only) or advisory-board-approved national exam; otherwise all out-of-state plumbers take the Washington exam.³

Fees

How to apply

1. Obtain DOH Backflow Assembly Tester certification.²
2. Submit an exam application to L&I with the fee, pass the exam, and pay the certificate fee within 90 days.²

Renewal

Renewal fee

$167.40⁹

Late renewal

Late renewal fee: $334.80⁹ (within 90 days after expiry)

If it expires

Submit active BAT evidence within 90 days of expiry or retest.²

More rules for this license are shared with other levels: group 1, group 2, group 4, group 5, group 6, group 10 and group 11 under Applies to every license level.

Limited volume domestic pump specialty plumber (PL03A)

Requirements

Experience

At least 2,000 hours of on-the-job training²
2,000 hours of supervised experience on pumping systems.²
Supervision: Supervision by an appropriate certified plumber.⁴

More rules for this license are shared with other levels: group 1, group 2, group 3, group 4, group 5, group 6, group 7, group 8, group 9, group 10, group 12 and group 14 under Applies to every license level.

Medical gas piping installer endorsement (MG01)

Journey level plumber endorsement for medical gas and vacuum piping (oxygen, nitrous oxide, nitrogen, medical air, vacuum).⁴

Requirements

Education or training

At least 32 clock hours⁴
At least 32 hours in an L&I-approved medical gas training course.⁴
Who may teach it: Training course provider approved by L&I with the advisory board; course fee paid to the provider.²

Experience

Must hold an active Washington journey level (PL01) certificate.²
License you must hold first: Active Washington journey level plumber certificate.¹

Exam

Medical gas written and practical competency examination (nationally recognized testing agency)²
Given by: PSI³
When you can take it: L&I approves eligibility (affidavits of experience and CE on file); the approval letter explains how to schedule with PSI. Approved applications are good for one year.³
Retakes: After a failure, submit a new application and $202.10 fee; keep working under supervision with an active trainee card until you pass. No limit on attempts.³
Time limit: Pay the certificate fee within 90 days of passing or retest.²
Exam waived: Reciprocity (Idaho, journey level only) or advisory-board-approved national exam; otherwise all out-of-state plumbers take the Washington exam.³

Fees

Each line is a separate charge as the board lists it. The board does not publish a combined total, so none is shown here.

How to apply

1. Hold an active PL01 certificate and complete 32 hours of approved medical gas training.⁴
2. Apply to L&I ($74.30), pass the written and practical exam, then pay the $166.90 endorsement fee.²

Renewal

Renewal fee

$166.90⁹

Required topics

Affidavit of continuity (brazing every 6 months) and affidavit of review of the current medical gas code.²

Late renewal

Late renewal fee: $333.80⁹ (within 90 days of expiry (double fee); 91+ days: re-examination)

If it expires

Expired 91+ days: retake the medical gas exam; no inactive status for endorsements.²

From another state

More rules for this license are shared with other levels: group 1, group 2, group 3 and group 5 under Applies to every license level.

Pump and irrigation specialty plumber (PL03)

Pumps, tanks, treatment and filtration equipment for drinking/irrigation water (no flow limit); electrical certification also required.⁴

Requirements

Experience

At least 4,000 hours of on-the-job training²
4,000 hours of supervised experience on pumping systems.²
Supervision: Supervision by an appropriate certified plumber.⁴

More rules for this license are shared with other levels: group 1, group 2, group 3, group 4, group 5, group 6, group 7, group 8, group 9, group 10, group 12 and group 14 under Applies to every license level.

Residential service plumber (PL04)

Service/repair/replacement of existing fixtures, piping and fittings outside the interior wall or above the floor in single-family homes and duplexes; drain cleaning and leak repair in any residential structure; no new construction.¹

Requirements

Experience

At least 4,000 hours of on-the-job training²
4,000 hours over at least two years; the first 2,000 hours/year under a journey level or residential specialty plumber, the second may be under a residential service plumber.²
Supervision: First year under PL01/PL02 direct supervision.²

Exam

Washington residential service plumber examination⁶
Given by: PSI³
When you can take it: L&I approves eligibility (affidavits of experience and CE on file); the approval letter explains how to schedule with PSI. Approved applications are good for one year.³
Retakes: After a failure, submit a new application and $202.10 fee; keep working under supervision with an active trainee card until you pass. No limit on attempts.³
Time limit: Pay the certificate fee within 90 days of passing or retest.²
Exam waived: Reciprocity (Idaho, journey level only) or advisory-board-approved national exam; otherwise all out-of-state plumbers take the Washington exam.³

More rules for this license are shared with other levels: group 1, group 2, group 3, group 4, group 5, group 6, group 7, group 9, group 10, group 11 and group 13 under Applies to every license level.

Residential specialty plumber (PL02)

All phases of plumbing in single-family dwellings, duplexes and apartment buildings up to three stories.⁴

Requirements

Experience

At least 6,000 hours of on-the-job training²
6,000 hours over at least three years under direct supervision of a certified residential specialty or journey level plumber.²
Supervision: Certified residential specialty or journey level plumber.⁴

Exam

Washington residential specialty plumber examination (closed book)⁶
Given by: PSI³
When you can take it: L&I approves eligibility (affidavits of experience and CE on file); the approval letter explains how to schedule with PSI. Approved applications are good for one year.³
Retakes: After a failure, submit a new application and $202.10 fee; keep working under supervision with an active trainee card until you pass. No limit on attempts.³
Time limit: Pay the certificate fee within 90 days of passing or retest.²
Exam waived: Reciprocity (Idaho, journey level only) or advisory-board-approved national exam; otherwise all out-of-state plumbers take the Washington exam.³

More rules for this license are shared with other levels: group 1, group 2, group 3, group 4, group 5, group 6, group 7, group 8, group 9, group 10, group 11, group 12 and group 13 under Applies to every license level.

Plumbing contractor license

Business license required (since July 1, 2021) to advertise, bid or perform plumbing work; scope follows the designated plumber's certificate (journey level = general, or specialty). Licensed plumbing contractors need not also register under RCW 18.27.¹

Requirements

Experience

Must employ a full-time journey level or specialty certified plumber as designated plumber (one at a time).¹
License you must hold first: Designated plumber with PL01 or specialty certificate.²

Background check

Background check required²

Insurance

Surety bond (or assigned savings account) of $6,000; up to $18,000 with residential final judgments in the past five years.²

Business requirements

UBI/business license with the Department of Revenue, Secretary of State filing for entities, workers' comp account; notarized application.²

Fees

Each line is a separate charge as the board lists it. The board does not publish a combined total, so none is shown here.

How to apply

1. Register the business with the Department of Revenue (UBI); entities file with the Secretary of State.⁵
2. Buy a $6,000 continuous plumbing contractor surety bond (or assign a savings account) and general liability insurance.⁵ Form (PDF, lni.wa.gov)¹³
3. Submit the notarized Application for Plumbing Contractor License (F627-051-000, $148.10) and Designated Plumber Assignment (F627-052-000, $53.20) at an L&I office or by mail.⁵ Form (PDF, lni.wa.gov)⁸

Renewal

How often

Every 2 years¹

From another state

More rules for this license are shared with other levels: group 1, group 3 and group 7 under Applies to every license level.

City and county rules

Backflow specialty plumber (PL30)No local plumber licenses: the state certificate lets the holder work in every city and county without any other license, permit or fee to engage in the work; cities and counties only issue plumbing permits.¹

Check a license or report a problem

Before you hire a plumber in Washington, you can confirm the license is current on the board's own search. Every board we cover in Washington is on the Washington license lookup page.

Look up a license

secure.lni.wa.gov⁵

Laws and rules

The requirements above come from these laws and board rules.

• Chapter 18.106 RCW (Plumbers)
• Chapter 296-400A WAC (Plumber certification rules)
• WAC 296-400A-045
• RCW 18.106.400-.440 (plumbing contractor license, bond, insurance)

Rule changes since January 2024

• July 1, 2026: Plumber fees raised (WSR 26-10-060): exam application $202.10, journey level/residential certificate $242.70 per 3 years, trainee $60.00, contractor license $148.10.²

Common questions

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