Process and Requirements to become a Plumbing Contractor In Washington State
If you're aiming to become a licensed plumber in Washington State, it's essential to understand the certification requirements and process overseen by the Washington State Department of Labor & Industries (L&I). This guide provides a comprehensive overview to help you navigate the steps toward licensure.
Step 1: Begin as a Plumber Trainee
To start your plumbing career in Washington, you must first obtain a plumber trainee certificate. This allows you to gain hands-on experience under the supervision of a certified plumber.
Requirements:
- Be at least 16 years old.
- Apply for a plumber trainee certificate through L&I.
- Work under the direct supervision of a certified plumber.
- Complete 8 hours of approved continuing education annually to renew your trainee certificate.
Step 2: Accumulate Required Work Experience
As a trainee, you'll need to log a specific number of supervised work hours, depending on the certification you aim to achieve:
- Journey Level (PL01): 8,000 hours (approximately 4 years), with at least 4,000 hours in commercial or industrial plumbing.
- Residential Specialty (PL02): 6,000 hours (approximately 3 years) in residential plumbing.
- Residential Service (PL04): 4,000 hours (approximately 2 years), with the first 2,000 hours under direct supervision.
- Pump and Irrigation (PL03): 4,000 hours (approximately 2 years) in the specialty, plus electrical certification.
- Domestic Well (PL03A): 2,000 hours (approximately 1 year) in the specialty, plus electrical certification.
- Backflow (PL30): Requires an active Backflow Assembly Tester (BAT) certification from the Washington State Department of Health.
Step 3: Apply for Certification and Pass the Exam
Once you've met the experience requirements, you can apply for the appropriate plumber certification and schedule your exam.
Application Process:
- Submit the Plumber Certification Application to L&I.
- Include affidavits of experience documenting your work hours.
- Pay the examination fee ($189.80 for most certifications).
- Upon passing the exam, pay the certification fee ($227.90 for journey level, residential, and residential service).
Exam Details:
- Administered by PSI at various locations across Washington.
- Covers topics such as plumbing codes, system design, and safety practices.
- A passing score is typically 70% or higher.
Step 4: Maintain Your Certification
Plumber certifications in Washington must be renewed every three years on your birthday. To renew, you must complete continuing education requirements:
- Journey Level, Residential, and Residential Service Plumbers: 24 hours of continuing education, including 12 hours of plumbing code and 4 hours of industry-related electrical.
- Pump and Irrigation, Domestic Well, and Backflow Plumbers: 24 hours of continuing education, with specific requirements based on the specialty.
Additional Considerations
- Reciprocity: Washington has reciprocal certification with Idaho for journey level plumbers. Out-of-state applicants from other states must provide documentation of equivalent experience or licensure for consideration.
- Contractor Licensing: If you plan to operate your own plumbing business, you must obtain a plumbing contractor license, which includes additional requirements such as bonding and insurance.
For more detailed information and to access application forms, visit the Washington State Department of Labor & Industries Plumber Certification page.
If you need assistance with insurance or bonding requirements, feel free to reach out for guidance tailored to your plumbing business needs.









