Plumber Certification. The Department of Labor and Industries (L&I) administers and enforces the plumbing trade laws.? To offer to do work, submit a bid, or perform, plumbing work, a person must have a plumbing contractor license, and a plumber must be certified as either a journey level or specialty plumber.

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To receive a journey level or specialty certificate, a person must meet certain work requirements and pass an examination.

To qualify as a journey level plumber, a person must have 8000 documented hours, and not less than four years, working as a plumber trainee under the supervision of a certified plumber. To qualify as a specialty plumber, the number of hours one must work to qualify varies by specialty. Specialties include residential, residential service, pump and irrigation, domestic well, and backflow.

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Plumber Trainees. Plumber trainees must have a trainee certificate and work under?supervision. Trainee certificates must be renewed annually. At the time of renewal, the trainee must provide L&I with an accurate list of employers and number of hours worked for each employer. Failure to provide hours worked is a violation subject to an infraction, and must result in the nonrenewal of the trainee certificate.?

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Trainee supervision must consist of a trainee being on the same jobsite of the supervising plumber. A journey level plumber, residential service plumber, or an appropriate specialty plumber must be on the same jobsite as the trainee for a minimum of 75 percent of each working day, or, under certain circumstances, available via mobile phone or a similar device that allows both audio and visual direction to the trainee. Remote supervision is only permitted when:

• the trainee has more than 2000 hours of training;
• the supervising plumber is not more than 40 miles from the jobsite; and
• the scope of work is service plumbing in a residential structure.?

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In 2020 the Legislature temporarily changed the required supervision ratios for plumber trainees. Until December 31, 2025, the ratio of trainees to certified journey level, residential service, or specialty plumbers working on a jobsite must be not more than:

• three trainees on any one residential structure jobsite for every certified specialty plumber or journey level plumber working as a specialty plumber;
• one trainee working on any one jobsite for every certified journey level plumber working as a journey level plumber; and
• one trainee working on any one jobsite for every certified residential service plumber.?

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After December 31, 2025, not more than two trainees may work on any residential structure jobsite for every certified specialty plumber or journey level plumber working as a specialty plumber.?

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Advisory Board of Plumbers.? The Advisory Board of Plumbers (Board) is a nine member board, appointed by the director of L&I, that conducts hearings on revocation and suspension of certificates, consents to any contract L&I enters into for the development and administration of required examinations, and otherwise advises L&I on all matters relative to the plumbing provisions.

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Beginning after the 2023 legislative session, and after the completion of the 2024 session, and every three years after that, the Board must convene a work group to evaluate the effects that the trainee ratio changes had on the industry, including public safety and industry response to demand for plumbing services. The work group must determine a sustainable plan for maintaining sufficient numbers of plumbers and trainees to safely meet the needs of the public and report to the Legislature by December 1st of each year the work group convenes.

The provision requiring that failure of a trainee to report plumbing hours worked for each employer is subject to an infraction and must result in a nonrenewal of a plumbing trainee certificate is removed.

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A provision requiring the trainee to be on the same jobsite as the supervising plumber is removed. Residential service plumbing trainees are allowed to work on separate residential structure jobsites performing residential service plumbing only in a like-in-kind manner. For remote supervision, it is specified that the trainee's scope of work is limited to the scope of a residential service plumber.

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The required supervision ratio for plumbing trainees working on a residential construction jobsite performing plumbing installation is no more than three trainees for every certified specialty plumber or journey level plumber working as a specialty plumber.

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The expiration date for the changes to the required supervision ratios for plumbing trainees is changed from December 31, 2025, to December 31, 2028.

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The term service plumbing is changed to residential service plumbing and the definition is modified so that residential service plumbing is limited to residential structures and the fixtures, fittings, and piping worked on are outside the interior walls or above the floor.

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The years in which the Board must convene a subgroup to evaluate the effects of the trainee ratio changes on the industry is changed from after the completion of the 2024 session to after the 2027 session.