Free Practice Test
Free Journeyman Plumber Practice Test
Take our free 10-question IPC/UPC practice test — written by master plumbers, aligned to modern plumbing code. No signup required. See your score instantly.
10 Free IPC/UPC Practice Questions
Q1. What is the minimum slope required for a 3-inch horizontal drain pipe?Show answer
✓ Correct Answer: 1/4 inch per foot
The IPC and UPC both require a minimum slope of 1/4 inch per foot (2%) for horizontal drain pipes 3 inches and smaller. Pipes 4 inches and larger may use 1/8 inch per foot.
Q2. What is the maximum horizontal distance allowed for a P-trap arm on a 1.5-inch drain?Show answer
✓ Correct Answer: 42 inches
Per the IPC, the maximum trap arm length for a 1.5-inch drain is 42 inches, but the practical maximum for code compliance without venting issues is typically 24–42 inches depending on jurisdiction.
Q3. A water heater pressure relief valve discharge pipe must terminate:Show answer
✓ Correct Answer: Within 6 inches of the floor
The IPC requires the T&P relief valve discharge pipe to terminate no more than 6 inches above the floor, into a drain, or to an indirect waste receptor to prevent scalding.
Q4. What is the minimum pipe size for a building sewer?Show answer
✓ Correct Answer: 4 inches
Per the IPC, the minimum diameter for a building sewer (the pipe running from the building to the public sewer) is 4 inches.
Q5. Which of the following materials is NOT approved for potable water supply piping?Show answer
✓ Correct Answer: ABS
ABS (Acrylonitrile Butadiene Styrene) is approved for DWV (drain, waste, vent) applications only — it is not approved for potable water supply piping. Copper, PEX, and CPVC are all used for water supply.
Q6. How many fixture units can a 3-inch stack carry?Show answer
✓ Correct Answer: 48 DFUs
Per IPC Table 710.1(1), a 3-inch drainage stack can carry 48 drainage fixture units (DFUs). This is a commonly tested calculation on the journeyman plumber exam.
Q7. A dishwasher drain must discharge through which device to prevent backflow?Show answer
✓ Correct Answer: An air gap
The IPC requires dishwasher drains to discharge through an air gap or connect to the high side of the garbage disposer to prevent contaminated water from siphoning back into the dishwasher.
Q8. What is the minimum clearance from the centerline of a toilet to a side wall or obstruction?Show answer
✓ Correct Answer: 15 inches
The IPC requires a minimum of 15 inches from the centerline of a water closet to any side wall or obstruction. Many jurisdictions follow the IRC which requires 15 inches as well.
Q9. Which type of pipe joint is required when connecting copper to galvanized steel pipe?Show answer
✓ Correct Answer: Dielectric union
A dielectric union is required when connecting copper and galvanized steel pipe to prevent galvanic corrosion, which occurs when dissimilar metals contact each other in a water system.
Q10. A wet vent must be sized for:Show answer
✓ Correct Answer: The total DFUs of all fixtures served
A wet vent must be sized for the total drainage fixture units of all the fixtures it serves, per IPC wet vent sizing tables. The minimum wet vent size is 2 inches but must be larger if DFU load requires it.
What Does the Journeyman Plumber Exam Cover?
The journeyman plumber exam focuses on the International Plumbing Code (IPC) or Uniform Plumbing Code (UPC), depending on your state. Key topics include: drainage, waste, and vent (DWV) system design; potable water supply sizing and materials; drainage fixture unit (DFU) calculations; trap sizing and venting requirements; backflow prevention; water heater installation; gas piping; and code-compliant rough-in layout. Most exams require familiarity with pipe sizing tables and the ability to calculate total fixture loads. Master plumbers emphasize that you must tab your code book and practice reading tables under timed conditions.
How Hard Is the Journeyman Plumber Exam?
The journeyman plumber exam difficulty varies by state — some states use standardized exams while others have state-specific tests. First-time pass rates typically range from 40–60% nationally. Most exams contain 80–150 questions with 4–6 hours to complete them. The challenge comes from heavy emphasis on code table navigation, DFU calculations, and the breadth of topics (from gas piping to backflow prevention). Candidates who fail often cite time pressure and unfamiliarity with their state's specific code edition.
How to Study for the Journeyman Plumber Exam
- 1.Know your state's code. Verify whether your state uses IPC or UPC, and check for state-specific amendments.
- 2.Drill DFU tables daily. Fixture unit calculations and pipe sizing are 30–40% of exam content.
- 3.Take timed practice exams. Full 80–150 question exams simulate real test conditions and build speed and confidence.
- 4.Use Plumber Prep by VoltExam. 1,000+ IPC/UPC practice questions, DFU calculator, offline access, and state-specific guides.
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