198+ Free Journeyman Plumber Practice Questions

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What is the minimum vertical distance required between a water service line and a sewer line when they cross each other?

6 inches

12 inches

18 inches

24 inches

to track

2026 Statistics

Key Facts: Journeyman Plumber Exam

70%

Passing Score

Most states

50-60%

Pass Rate

Varies by state

Questions

Typical exam length

3-4 hrs

Time Limit

State-dependent

$75-150

Exam Fee

PSI/Prometric

2024/2026

IPC/UPC Edition

Check your state

The Journeyman Plumber exam has a 50-60% pass rate in most states. The exam requires 70% to pass and covers 5 content domains based on IPC/UPC codes. Most states allow code books during the exam but require thorough knowledge of pipe sizing, venting, and plumbing calculations. The exam tests both theory and practical applications including isometric drawings and DFU calculations.

Sample Journeyman Plumber Practice Questions

Try these sample questions to test your Journeyman Plumber exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 198+ question experience with AI tutoring.

1What is the minimum vertical distance required between a water service line and a sewer line when they cross each other?

A.6 inches

B.12 inches

C.18 inches

D.24 inches

Explanation: When water and sewer lines cross, the water line must be at least 12 inches above the sewer line. If this vertical separation cannot be maintained, the sewer line must be constructed of approved pressure-rated material and pressure tested to ensure watertightness. This requirement protects the potable water supply from potential contamination.

2Which organization publishes the Uniform Plumbing Code (UPC)?

A.International Code Council (ICC)

B.International Association of Plumbing and Mechanical Officials (IAPMO)

C.National Fire Protection Association (NFPA)

D.American Society of Plumbing Engineers (ASPE)

Explanation: The Uniform Plumbing Code (UPC) is published by the International Association of Plumbing and Mechanical Officials (IAPMO). The UPC is developed using ANSI-accredited consensus procedures and is widely adopted throughout the United States, particularly in western states. The International Plumbing Code (IPC) is published by the ICC.

3What is the definition of a "DFU" (Drainage Fixture Unit)?

A.A measure of the discharge rate from a fixture in gallons per minute

B.A measure of the probable discharge into the drainage system by various types of plumbing fixtures

C.The total volume of water used by a fixture in a 24-hour period

D.The diameter of the drain pipe required for a specific fixture

Explanation: A Drainage Fixture Unit (DFU) is a measure of the probable discharge into the drainage system by various types of plumbing fixtures. It is used to size drainage piping systems. One DFU is equivalent to 7.5 gallons per minute (gpm) of flow. Different fixtures are assigned different DFU values based on their typical discharge characteristics.

4At what depth must buried plastic water piping be installed to protect it from damage?

A.6 inches below grade

B.12 inches below grade

C.18 inches below grade

D.24 inches below grade

Explanation: Buried plastic water piping must be installed at least 12 inches below grade to protect it from damage due to surface activities, freezing, and other hazards. In areas subject to heavy vehicle traffic or where local conditions warrant, greater depths may be required. The piping should also be bedded in sand or fine soil free from rocks and debris.

5What is the maximum allowable water velocity in copper tubing for water distribution systems?

A.4 feet per second

B.6 feet per second

C.8 feet per second

D.10 feet per second

Explanation: The maximum allowable water velocity in copper tubing for water distribution systems is 8 feet per second. Velocities exceeding this limit can cause erosion corrosion, noise, and water hammer. For water pressures above 80 psi, the velocity should be reduced to 4-6 feet per second to minimize these issues.

6When is a plumbing permit required according to most plumbing codes?

A.Only for new construction

B.For installation, alteration, or repair of plumbing systems

C.Only for commercial projects

D.Only when connecting to the municipal sewer

Explanation: A plumbing permit is typically required for the installation, alteration, or repair of plumbing systems. This includes new construction, remodels, water heater replacements, sewer line repairs, and fixture replacements in most jurisdictions. Minor repairs like faucet washer replacements usually do not require permits, but requirements vary by locality.

7What is the minimum size cleanout required for a 4-inch drain pipe?

A.2 inches

B.3 inches

C.4 inches

D.6 inches

Explanation: Cleanouts must be the same size as the pipe they serve, up to 4 inches. For pipes larger than 4 inches, the cleanout can be 4 inches. Therefore, a 4-inch drain pipe requires a 4-inch cleanout. This ensures proper access for drain cleaning equipment and effective cleaning of the entire pipe diameter.

8Which of the following materials is NOT approved for use in a potable water supply system?

A.Type K copper tubing

B.CPVC pipe (Schedule 40)

C.Lead pipe

D.PEX tubing (NSF-certified)

Explanation: Lead pipe is NOT approved for use in potable water supply systems due to the health hazards associated with lead contamination. The Safe Drinking Water Act and modern plumbing codes prohibit lead pipe and limit lead content in solder and flux to not more than 0.2%. Type K copper, CPVC, and NSF-certified PEX are all approved materials for potable water systems.

9What is the purpose of an air gap in a plumbing system?

A.To allow air to enter the drainage system

B.To prevent backflow by providing a physical separation between the water supply and the fixture

C.To reduce water hammer

D.To increase water pressure

Explanation: An air gap is the physical separation between the water supply and the flood level rim of a fixture or receptor. It is the most effective backflow prevention method because it creates a visible, unobstructed vertical distance (typically twice the supply pipe diameter, minimum 1 inch) that prevents contaminated water from being siphoned back into the potable water supply.

10How many DFUs is a standard residential washing machine rated for?

A.1 DFU

B.2 DFUs

C.3 DFUs

D.4 DFUs

Explanation: A standard residential clothes washing machine is rated at 2 DFUs (Drainage Fixture Units). This value is used when sizing the drainage piping system. The washing machine standpipe must be at least 2 inches in diameter and extend between 18 and 30 inches above the trap weir.

About the Journeyman Plumber Exam

State licensing exam based on IPC/UPC plumbing codes covering drainage, waste, venting, water supply, and gas piping systems. Tests 5 content domains including plumbing code general knowledge, DWV systems, water supply, gas piping, and fixtures/equipment. Passing certifies competence to install, maintain, and repair plumbing systems under supervision.

Questions

90 scored questions

Time Limit

3-4 hours

Passing Score

70%

Exam Fee

$75-$150 (PSI / State Licensing Boards)

Journeyman Plumber Exam Content Outline

30%

Plumbing Code & General Knowledge

IPC/UPC code structure, definitions, permit requirements, inspections, plumbing math, isometric drawings, materials standards, and general code compliance

25%

Drainage, Waste & Vent (DWV) Systems

Drainage pipe sizing, fixture units (DFU), vent types and sizing, trap seal protection, cleanouts, slopes, and DWV installation requirements

20%

Water Supply Systems

Water pipe sizing, WSFU calculations, backflow prevention, pressure requirements, water heaters, circulation systems, and cross-connection control

15%

Gas Piping

Gas pipe sizing, pressure testing, appliance venting, combustion air requirements, gas leak detection, and fuel gas code compliance

10%

Fixtures & Equipment

Fixture installation requirements, water closets, lavatories, bathtubs, showers, water heaters, sump pumps, ejectors, and special waste systems

How to Pass the Journeyman Plumber Exam

What You Need to Know

Passing score: 70%
Exam length: 90 questions
Time limit: 3-4 hours
Exam fee: $75-$150

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

Journeyman Plumber Study Tips from Top Performers

1Master DFU and WSFU calculations - pipe sizing is heavily tested on every exam

2Practice isometric drawing interpretation - you will need to visualize pipe layouts

3Memorize minimum pipe sizes for common fixtures and applications

4Understand venting requirements - know when different vent types are required

5Study water heater installation requirements including temperature and pressure relief valves

6Practice with timed exams - time management is critical for the calculations portion

7Learn to navigate the IPC/UPC index quickly - know where to find common tables

8Focus on backflow prevention device selection and installation requirements

Frequently Asked Questions

How hard is the Journeyman Plumber exam?

The exam is moderately difficult with pass rates around 50-60% in most states. The exam requires knowledge of IPC or UPC codes, pipe sizing calculations, and venting requirements. Many candidates find the isometric drawing interpretation and DFU calculations challenging. Most states allow code books but the time limit requires efficient code navigation.

What is the passing score?

Most states require 70% to pass the Journeyman Plumber exam. Some jurisdictions may require 75%. The exam typically has 80-125 questions depending on the state, with most states using 90-100 questions.

Can I use code books during the exam?

Most states allow bound copies of the IPC or UPC during the exam. No loose papers, handwritten notes, or electronic devices are permitted. Some states provide code books while others require you to bring your own. Always check with your specific state board for approved reference materials.

What code edition is used?

Most states have adopted the 2024 IPC and UPC editions, though some may still use the 2021 editions. The 2026 editions are being adopted by some jurisdictions. Check with your state licensing board to confirm which code edition is used for your exam.

How many questions are on the exam?

Most state exams contain 80-125 questions depending on the jurisdiction. The most common format is 90-100 multiple-choice questions. The exam is typically split between code knowledge, calculations, and practical applications like isometric drawings.

What is a plumbing fixture unit (DFU)?

A Drainage Fixture Unit (DFU) is a measure of the probable discharge into the drainage system by various types of plumbing fixtures. One DFU equals approximately 7.5 gallons per minute of flow. DFU values are used to size drainage and vent piping systems. Different fixtures have different DFU ratings - for example, a water closet is typically 3-4 DFUs while a lavatory is 1-2 DFUs.