Washington Plumber License Requirements

Official classification: Plumber Certification (Journey Level / Specialty) + Plumbing Contractor License · Issued by the Washington Department of Labor & Industries (L&I), Plumber Certification Program.

🔧 PlumberWA ✔ Verified 2026-06-22

In Washington, plumbers must hold the Plumber Certification (Journey Level / Specialty) + Plumbing Contractor License, issued by the Washington Department of Labor & Industries (L&I), Plumber Certification Program, and a $6,000 surety bond is required. Full requirements — experience, exams, fees, insurance, renewal and reciprocity — are detailed below.

How to become a licensed plumber in Washington

Follow these steps to earn your Plumber Certification (Journey Level / Specialty) + Plumbing Contractor License. Every figure is verified against the Washington Department of Labor & Industries (L&I), Plumber Certification Program; full detail for each step is further down the page.

Build the required experience. Journey Level: 4 years / 8,000 hours (minimum 2 years / 4,000 hours in commercial or industrial). Residential: 3 years / 6,000 hours. Residential Service: 2 years / 4,000 hours (first year under direct journey/residential supervision). Pump & Irrigation: 2 years / 4,000 hours. Domestic Well: 1 year / 2,000 hours. Backflow: Active BAT certification from WA Department of Health required.
Pass the Journey Level Plumber Exam and Residential Specialty Plumber Exam and Residential Service Plumber Exam and Pump & Irrigation / Domestic Well Exam exams. Providers, passing scores and fees are in the Exams section below.
Secure your surety bond. Washington requires $6,000 Washington Continuous Plumbing Contractor's Surety Bond (or assignment of savings) — plumbing contractor license only; no bond required for individual plumber certifications.
Line up insurance. You'll need liability insurance ($250,000 combined single limit per occurrence (plumbing contractor license); L&I must be listed as certificate holder. Insurance certificate must be renewed annually or contractor license is automatically suspended.), and workers' compensation coverage.
Clear the background check. Not publicly required by L&I for plumber certification or contractor license (official L&I pages do not mention a criminal background check requirement).
Submit your application and fees. Apply through the Washington Department of Labor & Industries (L&I), Plumber Certification Program — $189.80 (individual plumber certification application + exam); $139.10 (plumbing contractor license application); $56.40/year (plumber trainee annual certificate) application fee, plus a Journey/Residential/Residential Service: $227.90; Pump & Irrigation / Domestic Well: $228.00; Backflow: $157.20; Plumbing Contractor: $139.10 license fee. Processing time: Not publicly disclosed by L&I; initial applications must be submitted by mail. Contact L&I Plumber Certification at 360-902-5207.
Keep the license active. Renew individual plumber certifications: every 3 years on holder's birthdate. Plumbing contractor license: every 2 years from date of issuance., completing Journey Level / Residential: 24 hours before renewal (minimum 12 hours plumbing code, 4 hours industry-related electrical, 8 hours code/IRE/industry-related plumbing). Pump & Irrigation / Domestic Well: 24 hours (minimum 12 hours electrical, 12 hours plumbing). Backflow: Current BAT certification required. Medical Gas: Affidavit of Continuity.

License types

Plumber Trainee — Entry-level workers; may perform plumbing work only under direct supervision of a certified plumber. Annual registration required.
Journey Level Plumber (PL01) — Qualified to work on all phases of plumbing construction, including commercial and industrial.
Residential Plumber (PL02) — Limited to single-family homes, duplexes, and buildings three stories or fewer.
Residential Service Plumber (PL04) — Restricted to service and repair of existing fixtures outside walls or above floors in residential properties.
Pump & Irrigation Plumber (PL03) — Water acquisition, treatment, storage, and movement equipment installation.
Domestic Well Plumber (PL03A) — Drinking and irrigation water systems for pumps not exceeding 100 GPM or 7.5 HP single phase.
Backflow Assembly Tester (PL30) — Maintenance and repair of existing backflow prevention assemblies; requires current BAT certification from WA Department of Health.
Plumbing Contractor — Business-entity license required to contract for plumbing work. Must designate a certified journey level or specialty plumber.

Requirements at a glance

Experience required	Journey Level: 4 years / 8,000 hours (minimum 2 years / 4,000 hours in commercial or industrial). Residential: 3 years / 6,000 hours. Residential Service: 2 years / 4,000 hours (first year under direct journey/residential supervision). Pump & Irrigation: 2 years / 4,000 hours. Domestic Well: 1 year / 2,000 hours. Backflow: Active BAT certification from WA Department of Health required.
Application fee	$189.80 (individual plumber certification application + exam); $139.10 (plumbing contractor license application); $56.40/year (plumber trainee annual certificate)
License fee	Journey/Residential/Residential Service: $227.90; Pump & Irrigation / Domestic Well: $228.00; Backflow: $157.20; Plumbing Contractor: $139.10
Renewal fee	Journey/Residential/Residential Service: $227.90 every 3 years; Pump & Irrigation / Domestic Well: $228.00 every 3 years; Backflow: $157.20 every 3 years; Plumbing Contractor: $139.10 every 2 years; late renewal: double the standard fee
Renewal period	Individual plumber certifications: every 3 years on holder's birthdate. Plumbing contractor license: every 2 years from date of issuance.
Continuing education	Journey Level / Residential: 24 hours before renewal (minimum 12 hours plumbing code, 4 hours industry-related electrical, 8 hours code/IRE/industry-related plumbing). Pump & Irrigation / Domestic Well: 24 hours (minimum 12 hours electrical, 12 hours plumbing). Backflow: Current BAT certification required. Medical Gas: Affidavit of Continuity.
Bond required	$6,000 Washington Continuous Plumbing Contractor's Surety Bond (or assignment of savings) — plumbing contractor license only; no bond required for individual plumber certifications
Liability insurance	$250,000 combined single limit per occurrence (plumbing contractor license); L&I must be listed as certificate holder. Insurance certificate must be renewed annually or contractor license is automatically suspended.
Property damage	Included in $250,000 combined single limit
Workers' comp	Required through L&I state fund if the business employs workers (Washington is a monopolistic workers' compensation state).
Background check	Not publicly required by L&I for plumber certification or contractor license (official L&I pages do not mention a criminal background check requirement).
Credit requirement	None
Reciprocity	Idaho (journey level only — Idaho-licensed journey level plumbers may waive the trade exam portion of the Washington examination)
Processing time	Not publicly disclosed by L&I; initial applications must be submitted by mail. Contact L&I Plumber Certification at 360-902-5207.

Exams

Journey Level Plumber Exam	Provider: PSI (for L&I) · Passing: 70% or greater · Fee: $189.80 application/exam fee to L&I; additional PSI scheduling fee (amount not publicly listed)
Residential Specialty Plumber Exam	Provider: PSI (for L&I) · Passing: 70% or greater · Fee: $189.80 application/exam fee to L&I
Residential Service Plumber Exam	Provider: PSI (for L&I) · Passing: 70% or greater · Fee: $189.80 application/exam fee to L&I
Pump & Irrigation / Domestic Well Exam	Provider: PSI (for L&I) · Passing: 70% or greater · Fee: $189.80 application/exam fee to L&I

Preparing for the Plumber exam? State-specific contractor exam-prep courses help you pass the first time. Start exam prep →

Local / municipal notes

Seattle requires a separate City of Seattle plumbing permit and may impose additional local requirements. Only L&I-certified plumbers may legally perform plumbing work on someone else's property in Washington.

Frequently asked questions

How much does a Washington plumber license cost?

Application: $189.80 (individual plumber certification application + exam); $139.10 (plumbing contractor license application); $56.40/year (plumber trainee annual certificate). License: Journey/Residential/Residential Service: $227.90; Pump & Irrigation / Domestic Well: $228.00; Backflow: $157.20; Plumbing Contractor: $139.10. Renewal: Journey/Residential/Residential Service: $227.90 every 3 years; Pump & Irrigation / Domestic Well: $228.00 every 3 years; Backflow: $157.20 every 3 years; Plumbing Contractor: $139.10 every 2 years; late renewal: double the standard fee.

Do plumbers in Washington need a surety bond?

$6,000 Washington Continuous Plumbing Contractor's Surety Bond (or assignment of savings) — plumbing contractor license only; no bond required for individual plumber certifications

What experience is required for a Washington plumber license?

Journey Level: 4 years / 8,000 hours (minimum 2 years / 4,000 hours in commercial or industrial). Residential: 3 years / 6,000 hours. Residential Service: 2 years / 4,000 hours (first year under direct journey/residential supervision). Pump & Irrigation: 2 years / 4,000 hours. Domestic Well: 1 year / 2,000 hours. Backflow: Active BAT certification from WA Department of Health required.

Is insurance required for plumbers in Washington?

Liability: $250,000 combined single limit per occurrence (plumbing contractor license); L&I must be listed as certificate holder. Insurance certificate must be renewed annually or contractor license is automatically suspended. Workers' compensation: Required through L&I state fund if the business employs workers (Washington is a monopolistic workers' compensation state).

How often must a Washington plumber license be renewed?

Individual plumber certifications: every 3 years on holder's birthdate. Plumbing contractor license: every 2 years from date of issuance.. Continuing education: Journey Level / Residential: 24 hours before renewal (minimum 12 hours plumbing code, 4 hours industry-related electrical, 8 hours code/IRE/industry-related plumbing). Pump & Irrigation / Domestic Well: 24 hours (minimum 12 hours electrical, 12 hours plumbing). Backflow: Current BAT certification required. Medical Gas: Affidavit of Continuity.

Fees and rules change frequently (often annually). This page was last verified on 2026-06-22 — always confirm current requirements directly with the Washington Department of Labor & Industries (L&I), Plumber Certification Program before applying. This is not legal advice.