Free Practice Questions for WA Plumber
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Key Facts: WA Plumber Exam
70%
Passing Score
WA L&I
~100
Exam Questions
PSI exam format
3 hrs
Time Limit
PSI
UPC 2015
Code Base
Washington adoption
The Washington journeyman plumber exam is administered through PSI and overseen by L&I. The exam has approximately 100 questions with a 3-hour time limit, requiring 70% to pass. Washington uses the UPC 2015 with state amendments — a key distinction from IPC states. The UPC requires a 4-inch minimum building sewer and does not permit AAVs.
Sample WA Plumber Practice Questions
Try these sample questions to review concepts for the WA Plumber exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 298+ question experience with AI tutoring.
1Which agency oversees plumber licensing in Washington State?
2Washington State's plumbing code is based on which model code?
3What is the passing score required on the Washington journeyman plumber exam?
4Per the UPC, what is the minimum slope for a 4-inch horizontal drainage pipe?
5Per the UPC, what is the DFU (Drainage Fixture Unit) value for a water closet (flush tank type)?
6Per the UPC, what is the minimum building sewer size?
7Per the UPC, what is the maximum distance between cleanouts in a horizontal drainage line?
8Per the UPC, what is the minimum trap seal depth?
9Per the UPC, what is the maximum number of fixture units allowed on a 2-inch horizontal branch?
10Per the UPC, what type of fitting is required for a horizontal change of direction in a drainage system?
About the WA Plumber Exam
Washington journeyman plumber licensing exam administered by PSI and overseen by L&I. Based on the Uniform Plumbing Code (UPC) 2015 with Washington State amendments. Washington is one of the western states that uses the UPC rather than the IPC, which affects building sewer minimums, AAV usage, and other provisions.
Exam sponsor: Washington Department of Labor & Industries (L&I). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.
Questions
100 questions
Time Limit
3 hours
Passing Score
70%
Reported exam pass rate: ~50-60%. This describes exam candidates, not OpenExamPrep users or results from using our resources. Exam sponsor website
Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.
Our practice resources: topics covered
We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.
Drainage Systems
Drain pipe sizing, fixture units (DFU), slope requirements, cleanouts, 4-inch minimum building sewer, indirect waste, and special drainage per UPC 2015 with WA amendments
Water Supply Systems
Water pipe sizing, WSFU calculations, backflow prevention (RPZ/DCVA/AVB), pressure regulation, water heaters, and cross-connection control
Venting Systems
Vent sizing (half-drain rule), wet venting, circuit venting, vent termination, frost closure prevention, and trap seal protection — no AAVs under UPC
Fixtures & Appliances
Fixture installation, clearances (24-inch front clearance per UPC), accessible fixtures, commercial fixtures, and scald prevention
Gas Piping
Gas pipe sizing, BTU calculations, appliance venting, pressure testing, CSST bonding, and combustion air requirements
Code Administration & Materials
L&I licensing, permits, inspections, approved materials, joint methods, UPC vs IPC differences, and Washington-specific amendments
Preparing for the WA Plumber Exam
What You Need to Know
- Passing score: 70%
- Exam length: 100 questions
- Time limit: 3 hours
- Exam / certification fees: $189.80 (exam) + $227.90 (license) Official sources
Using Our Practice Resources
- Work through all 298 available questions
- Review every answer and explanation
- Track weak areas and revisit them
- Use our AI tutor for tough concepts
WA Plumber: Suggested Study Strategy
Frequently Asked Questions
How hard is the Washington journeyman plumber exam?
The Washington exam is challenging with an estimated 50-60% pass rate. It has approximately 100 questions based on the UPC 2015 with WA amendments and requires 70% to pass. The UPC has different provisions than the IPC used by many other states.
What plumbing code does Washington use?
Washington uses the Uniform Plumbing Code (UPC) 2015 edition with Washington State amendments. The UPC is published by IAPMO and differs from the IPC in areas like building sewer minimums (4 inches vs 3 inches) and AAV usage (not permitted under UPC).
How much does the Washington plumber exam and license cost?
The total cost is approximately $417.70: $189.80 for the PSI exam fee plus $227.90 for the L&I license fee. Check with L&I for current fee schedules.
What key differences exist between the UPC and IPC?
Key UPC differences: 4-inch minimum building sewer (vs 3-inch IPC), no air admittance valves (AAVs), 24-inch front clearance for water closets (vs 21-inch IPC), and the half-drain-diameter vent sizing rule.