Washington Plumbing 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 exam for the license class you are applying for. 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.
Check the insurance rules. Liability: Plumbing contractor license: $200,000 public liability + $50,000 property damage, or $250,000 combined single limit; L&I must be listed as certificate holder. Insurance certificate must be renewed annually or contractor license is automatically suspended. Property damage: $50,000 (standalone); or included in the $250,000 combined single limit. Workers' compensation: Required through L&I state fund if the business employs workers (Washington is a monopolistic workers' compensation state).
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 — $202.10 (individual plumber certification exam application); $148.10 (plumbing contractor license); $60.00 per year (plumber trainee certificate) (WAC 296-400A-045, effective 2026-07-01) application fee, plus a Journey/Residential/Residential Service: $242.70; Domestic Pump: $242.80; Backflow: $167.40; Plumbing Contractor: $148.10 license fee. Processing time: Exam applications are accepted online or by mail and processed first-come, first-served. Contact L&I Plumber Certification at 360-902-5207.
Keep the license active. Renewal: 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.

For the general path in every state, see the Plumber guide →

Washington plumber license lookup

To confirm a plumber is properly licensed in Washington — or to check the status of your own license — search the issuing agency's official license database. The record shows whether the license is active and in good standing.

Verify a license now: Search the official secure.lni.wa.gov database →

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	$202.10 (individual plumber certification exam application); $148.10 (plumbing contractor license); $60.00 per year (plumber trainee certificate) (WAC 296-400A-045, effective 2026-07-01)
License fee	Journey/Residential/Residential Service: $242.70; Domestic Pump: $242.80; Backflow: $167.40; Plumbing Contractor: $148.10
Renewal fee	Journey/Residential/Residential Service: $242.70 every 3 years; Domestic Pump: $242.80 every 3 years; Backflow: $167.40 every 3 years; Plumbing Contractor: $148.10 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	Plumbing contractor license: $200,000 public liability + $50,000 property damage, or $250,000 combined single limit; L&I must be listed as certificate holder. Insurance certificate must be renewed annually or contractor license is automatically suspended.
Property damage	$50,000 (standalone); or included in the $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): Washington has reciprocal certification with Idaho for journey level plumbers, who may be certified without the Washington exam (RCW 18.106.155; WAC 296-400A-070). All other plumbers must pass the Washington exam. · compare all states
Processing time	Exam applications are accepted online or by mail and processed first-come, first-served. Contact L&I Plumber Certification at 360-902-5207.

What a Washington plumber license costs

Application fee	$202.10 (individual plumber certification exam application); $148.10 (plumbing contractor license); $60.00 per year (plumber trainee certificate) (WAC 296-400A-045, effective 2026-07-01).
License fee	Journey/Residential/Residential Service: $242.70; Domestic Pump: $242.80; Backflow: $167.40; Plumbing Contractor: $148.10.
Journey Level Plumber Exam	$202.10 exam application fee to L&I (WAC 296-400A-045); additional PSI scheduling fee (amount not publicly listed).
Residential Specialty Plumber Exam	$202.10 exam application fee to L&I (WAC 296-400A-045).
Residential Service Plumber Exam	$202.10 exam application fee to L&I (WAC 296-400A-045).
Pump & Irrigation / Domestic Well Exam	$202.10 exam application fee to L&I (WAC 296-400A-045).
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. A bond's premium is a percentage of the bond amount, set by the surety.
Renewal fee	Journey/Residential/Residential Service: $242.70 every 3 years; Domestic Pump: $242.80 every 3 years; Backflow: $167.40 every 3 years; Plumbing Contractor: $148.10 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.

Exams

Journey Level Plumber Exam	Provider: PSI (for L&I) · Passing: 70% or greater · Fee: $202.10 exam application fee to L&I (WAC 296-400A-045); additional PSI scheduling fee (amount not publicly listed)
Residential Specialty Plumber Exam	Provider: PSI (for L&I) · Passing: 70% or greater · Fee: $202.10 exam application fee to L&I (WAC 296-400A-045)
Residential Service Plumber Exam	Provider: PSI (for L&I) · Passing: 70% or greater · Fee: $202.10 exam application fee to L&I (WAC 296-400A-045)
Pump & Irrigation / Domestic Well Exam	Provider: PSI (for L&I) · Passing: 70% or greater · Fee: $202.10 exam application fee to L&I (WAC 296-400A-045)

Renewing a Washington plumber license

The Plumber Certification (Journey Level / Specialty) + Plumbing Contractor License renews on a fixed cycle set by the Washington Department of Labor & Industries (L&I), Plumber Certification Program. Finish the continuing-education requirement before you file — boards generally will not process a renewal without it. Late and lapsed renewals are handled differently by every board, so check the renewal page linked below before the deadline passes.

Renewal period	Individual plumber certifications: every 3 years on holder's birthdate. Plumbing contractor license: every 2 years from date of issuance.
Renewal fee	Journey/Residential/Residential Service: $242.70 every 3 years; Domestic Pump: $242.80 every 3 years; Backflow: $167.40 every 3 years; Plumbing Contractor: $148.10 every 2 years; late renewal: double the standard fee
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.
Where to renew	Washington Department of Labor & Industries (L&I), Plumber Certification Program

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: $202.10 (individual plumber certification exam application); $148.10 (plumbing contractor license); $60.00 per year (plumber trainee certificate) (WAC 296-400A-045, effective 2026-07-01). License: Journey/Residential/Residential Service: $242.70; Domestic Pump: $242.80; Backflow: $167.40; Plumbing Contractor: $148.10. Renewal: Journey/Residential/Residential Service: $242.70 every 3 years; Domestic Pump: $242.80 every 3 years; Backflow: $167.40 every 3 years; Plumbing Contractor: $148.10 every 2 years; late renewal: double the standard fee.

How do I look up a plumber license in Washington?

Search the official license database at secure.lni.wa.gov. The record shows whether the license is active and in good standing.

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: Plumbing contractor license: $200,000 public liability + $50,000 property damage, or $250,000 combined single limit; L&I must be listed as certificate holder. Insurance certificate must be renewed annually or contractor license is automatically suspended. Property damage: $50,000 (standalone); or included in the $250,000 combined single limit. Workers' compensation: Required through L&I state fund if the business employs workers (Washington is a monopolistic workers' compensation state).

How long does it take to get a Washington plumber license?

Processing time: Exam applications are accepted online or by mail and processed first-come, first-served. Contact L&I Plumber Certification at 360-902-5207.

Is a background check required for plumbers in Washington?

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).

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.