Plumber Trainee

To learn the plumbing trade in Washington State and become a certified plumber, you must start as a plumber trainee. As a trainee, you will work under the direct supervision of a certified plumber and learn through on-the-job training. Once you have the required experience and education, you can take the plumber exam to become a certified plumber or journey level plumber.

Getting Started

Plumber trainees must:

• Apply for a plumber trainee certificate.
• Be 16 or older.
• For information about minors working on construction sites, contact Employment Standards.
• Work under the direct supervision of a journey level or certified plumber.
• Get the required number of years and hours of experience to qualify for the state plumber examination.
• Have an electrical trainee card if working in the pump and irrigation or domestic pump trade.
• Take 8 hours of approved continuing education instruction yearly to renew their certificate.
  • For questions about continuing education requirements, call the Plumber Certification Program at 360-902-5207 or email plumbers@Lni.wa.gov.

Reporting your hours of experience

Plumber trainees must report their supervised work hours at least once a year by filing affidavits of experience (F627-004-000) and/or residential service affidavit of experience  with L&I. These affidavits report the qualifying, supervised hours a trainee has worked, and who their supervising plumber was. We verify all affidavits and log creditable hours as trainees work toward certification.

Affidavits should be sent in no later than 30 days after your renewal date. Trainees must submit separate, notarized affidavits to report hours worked for each employer, registered contractor, and/or supervising plumber during the previous year.

Trainees may not receive credit for any hours of experience:

• If they are not properly supervised.
• From incorrectly completed affidavits of experience.
• While their certificate is expired or inactive.
• If they have outstanding penalties.
• While working for out-of-state employers.
• From out-of-state trainee or apprenticeship programs.

Reconsideration available

If you receive a decision that denies audited training hours, you can request a reconsideration. There is no fee for filing a request, which must be made within 20 calendar days of the date on the initial denial letter you received. The request must include specific reasons why the denial should be reconsidered along with a copy or photo of the letter you received.

Send the request to HoursReconsideration@Lni.wa.gov.

See RCW 18.106.070 (2) and WAC 296-400A-120 (4) for detailed information on affidavits of experience.

Tracking your hours of experience

It is the trainee’s responsibility to submit each of their affidavits to L&I by their renewal date. To ensure the accuracy of hours reported on affidavits, trainees should keep a personal training log to track their hours. For an example, refer to our sample training log. A trainee’s log is strictly for their record keeping. It is not an acceptable form of documentation for contractors.