Thinking about launching a plumbing career in the Evergreen State? You’re not alone—Washington’s growing population and aging infrastructure are driving strong demand for skilled tradespeople. But before you can legally install pipes or fix leaks for pay, you must know how to get a plumbing license in Washington State. This guide walks you through every requirement, timeline, and insider tip you need to succeed—no guesswork, just clear, actionable steps.
What Type of Plumbing License Do You Need in Washington?
Washington State issues three main plumbing license types, each with distinct qualifications:
- Apprentice Plumber License – Entry-level; allows you to train under a certified journey-level or master plumber.
- Journey-Level Plumber License – For experienced plumbers who can work independently.
- Master Plumber License – Required to pull permits, supervise others, or run your own plumbing business.
Most people start as apprentices. According to the Washington State Department of Labor & Industries (L&I), over 1,200 new plumbing apprentices register each year—proof of the trade’s steady growth.
💡 Pro Tip: You cannot skip the apprentice stage. Washington requires documented on-the-job training before you qualify for journey-level status.
Step-by-Step: How to Get a Plumbing License in Washington State
Step 1: Meet Basic Eligibility Requirements
Before applying, ensure you meet these criteria:
- Be at least 16 years old (for apprentice license)
- Have a valid Social Security Number or ITIN
- Be legally authorized to work in the U.S.
- Provide proof of 8,000 hours (≈4 years) of supervised plumbing experience for journey-level (not required for apprentice)
Step 2: Register as an Apprentice
All plumbing apprentices in Washington must register with L&I within 30 days of starting work. Here’s how:
- Find a certified journey-level or master plumber to supervise you.
- Complete the Apprentice Application on the L&I website.
- Pay the $50 registration fee (as of 2025).
- Renew annually—yes, even if you’re still training.
⚠️ Warning: Working without a registered apprentice license is illegal and can result in fines up to $1,000 per violation.
Step 3: Complete Required Training Hours
To qualify for the journey-level exam, you need:
- 8,000 hours of hands-on plumbing work (minimum 4 years)
- 400+ hours of classroom or online technical instruction
These hours must be verified by your supervising plumber and submitted to L&I. Many apprentices complete training through state-approved programs like those at Bates Technical College or Lake Washington Institute of Technology.
Step 4: Apply for the Journey-Level Plumbing Exam
Once you’ve logged your hours:
- Submit your Journey-Level Application to L&I.
- Include proof of experience and training.
- Pay the $138 exam fee.
- Schedule your test through PSI Exams, the state’s testing vendor.
The exam covers:
- Washington plumbing code (based on the Uniform Plumbing Code)
- Drainage, venting, water supply, and gas piping
- Safety and backflow prevention
📊 Pass Rate Insight: Only about 62% of first-time test-takers pass. Thorough prep is essential.
Step 5: Pass the Exam & Get Licensed
- The exam has 100 multiple-choice questions; you need 70% to pass.
- You’ll receive results immediately after testing.
- If you pass, L&I issues your Journey-Level Plumber License within 2–3 weeks.
- License renewal is required every 2 years ($107 fee).
How Long Does It Take to Get Licensed?
| Apprentice | Immediate (after registration) | Sponsor + $50 fee |
| Journey-Level | 4–5 years | 8,000 work hours + 400 class hours + exam |
| Master Plumber | 6+ years | 2+ years as journey-level + additional exam |
🕒 Real-World Example: Maria, a Seattle resident, started as an apprentice in 2021. By logging 2,000 hours/year and taking night classes, she passed her journey exam in early 2025—right on schedule.
Costs Breakdown: What to Budget For
| Apprentice Registration | $50 |
| Journey-Level Exam Fee | $138 |
| Journey License (initial) | Included |
| Biennial Renewal | $107 |
| Training Courses (optional) | $500–$2,500 |
| Study Materials | $50–$150 |
Total estimated cost (excluding training): ~$295 to get licensed.
Common Mistakes to Avoid
- ❌ Not registering as an apprentice – Even unpaid work requires registration.
- ❌ Missing classroom hours – L&I strictly enforces the 400-hour rule.
- ❌ Using outdated codebooks – Washington adopts the 2021 Uniform Plumbing Code with state amendments.
- ❌ Ignoring renewal deadlines – Lapsed licenses require reinstatement fees.
For official code references, see the Uniform Plumbing Code overview on Wikipedia —though always cross-check with L&I’s latest guidelines.
FAQ: How to Get a Plumbing License in Washington State
Q: Can I get a plumbing license in Washington with out-of-state experience?
A: Yes—but you must still meet Washington’s 8,000-hour requirement. L&I may accept verified out-of-state hours, but you’ll likely need to take the Washington-specific exam. Reciprocity is not automatic.
Q: Do I need a high school diploma?
A: No, but it’s strongly recommended. Most training programs and employers require it. Basic math and reading skills are essential for reading blueprints and calculating pipe slopes.
Q: How hard is the Washington plumbing exam?
A: It’s challenging but passable with preparation. Focus on Washington amendments to the Uniform Plumbing Code, especially sections on seismic bracing and rainwater harvesting—topics unique to the Pacific Northwest.
Q: Can I work while waiting for my license?
A: Only as a registered apprentice under direct supervision. Once you pass the journey exam, you can work independently—but you must have your physical license card before doing so.
Q: Are there continuing education requirements?
A: Not for journey-level plumbers—but master plumbers must complete 16 hours of continuing education every 2 years to renew.
Q: What if I fail the exam?
A: You can retake it after 30 days. Each retake costs $138. Most candidates pass by the second attempt with focused study.
Final Thoughts: Your Future Starts with One Pipe
Knowing how to get a plumbing license in Washington State isn’t just about checking boxes—it’s your ticket to a stable, well-paid career in a field that’s always in demand. With median wages over $78,000/year (BLS, 2024) and strong job growth projected through 2030, plumbing offers real financial security.
If this guide helped you map your path, share it with a friend considering a trade career! 👷♂️
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Ready to turn wrenches into wages? Your journey starts today—with a single registration.
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