Certification

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Plumbers in Washington must be certified by Labor and Industries

Get or renew your certification ...

Online

• Plumber (or backflow) Trainee.
• Journeyman Plumber (residential or backflow specialties).
• Medical Gas Endorsement.
• Well Drillers License.

Please note: New applications and renewals submitted online between the hours of 6 p.m. and 3 a.m. may not be updated for up to 48 hours.

By mail

• Print the below application for the plumber certification examination, the medical gas piping installer endorsement or reciprocal certification.
• Plumber Certification Application (281 KB PDF / 3 min.)

In person

• At any L&I field office

See also:

• Plumber Training and Continuing Education
  Find out about plumber exams, fees, training for the Medical Gas Piping Installer Endorsement, and continuing education requirements.
• View Contractor and Plumber Infractions
  A quarterly listing of infractions issued for contractor registration and plumber certification problems. If you have questions, contact the Infraction Section - E-mail: sayb235@lni.wa.gov - Phone: 360-902-5205.

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For more information:

Facts About State Certification for Plumbers (69 KB PDF)
- Get an overview of the requirements and process and frequently asked questions.