1.1 Washington Plumber Certification Law: RCW 18.106, WAC 296-400A, Trainees, & Supervision

Why Licensing Law Matters Before You Study Code

The Washington journey level exam itself is built from the Uniform Plumbing Code (UPC), but you only reach the exam by satisfying Washington's certification law. Knowing the rules also protects your hours: trainee time that is worked out of ratio, on an expired card, or without the required continuing education is simply not credited. Two legal texts govern everything in this section:

1. Chapter 18.106 RCW (Plumbers), the statute passed by the Legislature. It requires a certificate, defines trainee supervision, sets renewal, and creates civil infractions.
2. Chapter 296-400A WAC (Plumber Certification Rules), the Department of Labor & Industries (L&I) rules that implement the statute: certificate types, exam eligibility, continuing education, fees, and the penalty schedule.

Under RCW 18.106.020, no person may engage in the trade of plumbing without a certificate, temporary permit, or trainee certificate and photo identification in their possession. L&I also requires the certificate to be worn and visibly displayed on the job.

Certificate Types and Scope (WAC 296-400A-010)

A medical gas piping installer endorsement is separate. Only an active Washington journey level plumber may apply for it.

Exam Eligibility and Fees

WAC 296-400A-121 sets the experience you must document before L&I approves a journey level exam application:

• 8,000 hours and not less than four years of documented training.
• Those hours must include 4,000 hours of commercial plumbing experience under the direct supervision of a certified journey level plumber.
• 16 hours of approved continuing education, including at least 4 hours of industry-related electrical training, completed before testing.

WAC 296-400A-045 sets L&I's fees. The journey level exam application fee is $202.10 per exam and is nonrefundable. The journey level certificate (first card or renewal) is $242.70 for three years, and a trainee certificate is $60.00. PSI charges its own separate scheduling fee (see Section 14.1). After you pass, you have 90 days to pay the certification fee. If you miss that deadline, you must retest (WAC 296-400A-020).

Trainee Certificates, Hours, and Continuing Education

• Every apprentice or learner must hold a plumbing training certificate. It is valid for one year and must be renewed annually (RCW 18.106.070; WAC 296-400A-120).
• Trainees need 8 hours of approved continuing education per year. Over a two-year period, those hours must include at least 8 hours of plumbing code and 4 hours of electrical training.
• At renewal, the trainee submits signed, notarized affidavits of experience listing each employer and the hours worked by category. Hours are due within 30 days after the trainee certificate's renewal date. If they are late, the trainee may lose credit for them.
• Hours worked while a trainee card is expired or inactive are not credited. Hours are also not credited while the trainee owes outstanding penalties.

Certified plumbers renew every three years on or before their birthdate (RCW 18.106.070). Journey level renewal requires 24 hours of approved continuing education, with at least 12 hours of plumbing code and 4 hours of electrical. The remaining 8 hours may be plumbing or electrical. If you renew late, you pay a doubled fee. If you do not renew within 90 days of the renewal date, you must retake the examination.

Supervision Ratios

The ratio rules in RCW 18.106.070(4) and WAC 296-400A-120(3) apply until December 31, 2028:

The supervising plumber must be on the same job site for at least 75% of each working day. The statute allows a narrow remote-supervision option by live audio and video. It applies only when the trainee has more than 2,000 hours, the supervisor is within 40 miles, and the work is residential service plumbing. Apprentices and approved trade-school trainees may work without direct on-site supervision during the last six months of their required experience.

Infractions, Appeals, and Reciprocity

Violations of RCW 18.106 are civil infractions. Each day and each job site in violation is a separate infraction. WAC 296-400A-400 sets escalating penalties:

To contest a notice of infraction, file a notice of appeal with L&I within 20 days of service, together with a $200 certified check. An administrative law judge at the Office of Administrative Hearings decides the appeal (RCW 18.106.200).

Washington has a reciprocal journey level agreement with Idaho. Other out-of-state plumbers must pass the Washington exam. Out-of-state journey level plumbers from non-reciprocal states may qualify for a temporary permit valid for 120 days ($100.30).