Journeyman Plumber Exam — Questions and Answers

Question 1: What is the greatest possible separation between an accessible toilet faucet and the front edge of the toilet?

25 inches (Correct answer)
18 inches
28 inches
16 inches

Correct answer: 25 inches

When the fixture is meant for handicap usage, bathroom faucets must be placed no more than 25 inches from the front border of the lavatory they are serving.

Question 2: A Temperature and Pressure (T&P) relief valve on a water heater must have its temperature-sensing element installed in a specific location to function correctly. Where must this element be located?

Within the top 6 inches of the tank. (Correct answer)
In the cold water inlet pipe.
At the midpoint of the water heater tank.
Within the bottom 6 inches of the tank.

Correct answer: Within the top 6 inches of the tank.

The T&P valve's temperature-sensing element must be immersed in the hottest water of the tank to provide accurate protection against excessive temperatures. The hottest water is always in the top 6 inches of a storage-type water heater. Installing it elsewhere could create a thermal lag, delaying its activation and creating a safety hazard.

Question 3: What is the purpose of a vacuum breaker installed on a hose bibb?

To regulate water pressure at the outlet
To reduce water hammer when the hose is disconnected
To prevent backflow of contaminated water into the potable supply (Correct answer)
To allow air into the pipe to speed drainage

Correct answer: To prevent backflow of contaminated water into the potable supply

A hose bibb vacuum breaker prevents back-siphonage of potentially contaminated water (from a submerged hose end) into the potable supply.

Question 4: A plumber is installing 1-inch Schedule 40 steel pipe for a horizontal natural gas run. According to common piping standards (ASME B31.1), what is the maximum recommended support spacing for this horizontal pipe?

8 feet (Correct answer)
4 feet
6 feet
12 feet

Correct answer: 8 feet

While specific local codes may vary, standard engineering practices such as those referenced in ASME B31.1 provide tables for maximum support spacing. For 1-inch nominal steel pipe, the suggested maximum span is typically around 8 feet for gas service to prevent sagging and stress on the joints. Some tables might show 9 feet, but 8 feet is a very common and safe standard.

Question 5: Where must a temperature and pressure (T&P) relief valve discharge pipe terminate?

At least 24 inches above the floor
Into the cold water supply line
Directly into a floor drain
Within 6 inches of the floor (Correct answer)

Correct answer: Within 6 inches of the floor

T&P relief valve discharge pipes must terminate within 6 inches of the floor to direct scalding water safely downward away from occupants.

Question 6: A plumber is installing a gas line to a new furnace. To protect the appliance's controls from particulate matter, a sediment trap is required. Based on model fuel gas codes, which of the following describes the correct installation of a sediment trap?

On the vertical pipe dropping down to the appliance, with gas flow passing straight through the tee.
Upstream of the appliance shutoff valve, as close to the main as possible.
Only on appliances located in basements or crawlspaces.
Downstream of the appliance shutoff valve and before the flexible appliance connector. (Correct answer)

Correct answer: Downstream of the appliance shutoff valve and before the flexible appliance connector.

Fuel gas codes require a sediment trap to be installed downstream of the appliance's shutoff valve, as close to the inlet of the appliance as practical, and before any flexible connector. It must be configured with a tee fitting to force a 90-degree change in gas flow, allowing sediment to fall into the capped nipple.

Question 7: What is the primary purpose of a plumbing vent system in a drainage, waste, and vent (DWV) installation?

To equalize atmospheric pressure within the drainage system, protecting trap seals. (Correct answer)
To increase the velocity of wastewater flowing through the pipes.
To provide a direct path for sewer gas to escape the building.
To serve as an overflow for the drainage system in case of a blockage.

Correct answer: To equalize atmospheric pressure within the drainage system, protecting trap seals.

The primary function of a vent system is to allow air to enter the drainage pipes. This prevents the formation of negative pressure (a vacuum) that could siphon water out of fixture traps. By protecting the trap seals, the vent system prevents dangerous sewer gases from entering the living space.

Question 8: A newly installed copper potable water distribution system in a commercial building must be tested for leaks. According to most model plumbing codes, what is the minimum required hydrostatic test pressure?

Equal to the street main pressure
100 psi or the working pressure, whichever is less
1.25 times the working pressure
1.5 times the working pressure, but not less than 100 psi (Correct answer)

Correct answer: 1.5 times the working pressure, but not less than 100 psi

Most plumbing codes, including the International Plumbing Code (IPC) and Uniform Plumbing Code (UPC), require a hydrostatic test pressure of at least 1.5 times the system's working pressure. Additionally, there is often a minimum requirement, typically 100 psi, to ensure a thorough test even in low-pressure systems. This high pressure will reveal any leaks at joints or defects in the piping.

Question 9: A plumber is installing a horizontal 3-inch drainage pipe. According to most model plumbing codes, what is the minimum required slope or grade for this pipe?

1/2 inch per foot
1 inch per foot
1/4 inch per foot (Correct answer)
1/8 inch per foot

Correct answer: 1/4 inch per foot

For horizontal drainage pipes 3 inches in diameter or smaller, the standard minimum slope required by most plumbing codes is 1/4 inch per foot. This ensures that solid waste is carried along with the liquids and prevents blockages. While a 1/8 inch per foot slope may be permissible for pipes 4 inches or larger in some jurisdictions, 1/4 inch per foot is the standard for 3-inch pipes.

Question 10: Under which of the following circumstances is a combination waste and vent system typically permitted by most plumbing codes?

As a primary venting method for multi-story residential buildings to save on piping materials.
For venting any residential bathroom group, including toilets, lavatories, and showers.
In any commercial kitchen application involving three-compartment sinks and food waste disposers.
For floor drains and sinks in specific applications like laboratories where conventional venting is structurally impractical. (Correct answer)

Correct answer: For floor drains and sinks in specific applications like laboratories where conventional venting is structurally impractical.

Combination waste and vent systems are specialized systems permitted only where structural conditions prevent the installation of a conventional vent system. They are typically used for fixtures like floor drains and sinks in locations such as laboratories or island sinks, where the oversized horizontal drain pipe also serves as the vent.

Question 11: A plumber is setting a water closet in a residential bathroom. According to the International Plumbing Code (IPC), what is the MINIMUM required clearance from the centerline of the water closet to an adjacent side wall or vanity?

12 inches
18 inches
15 inches (Correct answer)
21 inches

Correct answer: 15 inches

IPC Section 405.3.1 specifies the minimum spacing for plumbing fixtures to ensure accessibility and ease of use. A water closet cannot be set closer than 15 inches from its center to any side wall, partition, or vanity.

Question 12: The least amount of time that the system must be evaluated when evaluating gas piping installed in a single-family home with a volume of less than 10 cubic feet is _________________.

60 minutes
30 minutes
15 minutes
10 minutes (Correct answer)

Correct answer: 10 minutes

A test that is sustained for a minimum of 10 minutes is required for gas piping that is installed in a single-family residence and has a volume of less than 10 cubic feet. More than 24 hours cannot be spent maintaining testing. A manometer is the most widely used testing tool.

Question 13: An isometric drawing shows a horizontal pipe run that must clear an obstruction by using a vertical offset. If the developed length (travel) of the pipe between the two 45-degree fittings is 50 inches, what is the vertical height (offset) gained?

50 inches
70.7 inches
25 inches
35.35 inches (Correct answer)

Correct answer: 35.35 inches

To find the offset (vertical height) from a known travel length in a 45-degree offset, divide the travel length by the constant 1.414 or multiply by 0.707. Calculation: 50 inches / 1.414 = 35.36 inches.

Question 14: The minimum slope for a 3-inch horizontal drain pipe under IPC is:

1/2 inch per foot
1/8 inch per foot
1 inch per foot
1/4 inch per foot (Correct answer)

Correct answer: 1/4 inch per foot

A 3-inch drain pipe requires a minimum slope of 1/4 inch per foot to ensure proper self-scouring flow.

Question 15: Which of the following locations is explicitly prohibited for the installation of a gas shutoff valve according to most model fuel gas codes?

Within a furnace plenum or concealed location (Correct answer)
Outdoors, adjacent to the gas meter
In a utility closet with other mechanical equipment
In the same room as the appliance

Correct answer: Within a furnace plenum or concealed location

The International Fuel Gas Code (IFGC) specifically prohibits the installation of shutoff valves in concealed locations and within furnace plenums. This is to ensure the valve is always accessible for emergency shutoff and to prevent the possibility of a gas leak directly entering the conditioned air distribution system.

Question 16: In an isometric plumbing drawing, a pipe is shown as a vertical line. It then turns and runs horizontally away from the viewer and to the right. Which of the following best describes how the horizontal pipe would be drawn?

As a line angled at 30 degrees up from the horizontal. (Correct answer)
As a horizontal line running straight to the right.
As a line angled at 45 degrees up from the horizontal.
As a vertical line running down.

Correct answer: As a line angled at 30 degrees up from the horizontal.

In standard isometric drawings, vertical lines are drawn vertically, while horizontal lines (representing length and width) are drawn at 30 degrees to the horizontal plane to create a three-dimensional view on a two-dimensional surface.

Question 17: Where the stack and its offset are functioning ____________ as a building drain, vertical offset vents are not needed.

sized (Correct answer)
identified
excluded
wet vented

Correct answer: sized

Where a stack and its offset are sized as building drains, vents for vertical offsets are not necessary. Vent pipes frequently have a diameter that is less than the drain they support. The vent is exempt from some vent rules, though, if it has the same diameter as the drain it is feeding. In this instance, it means that vertical offset venting is not required for vents with diameters equivalent to the drains being supplied.

Question 18: To prevent scalding, most plumbing codes mandate that the hot water supplied to residential bathtubs and showers be limited to a maximum temperature by a temperature-limiting device. What is this maximum temperature?

130°F (54°C)
110°F (43°C)
120°F (49°C) (Correct answer)
140°F (60°C)

Correct answer: 120°F (49°C)

To protect users, especially children and the elderly, from severe burns, plumbing codes and safety standards generally require that the maximum temperature of water delivered from fixtures like showers and tubs be limited to 120°F (49°C).

Question 19: When is a cleanout appropriate for a new fixture installation? What, in other words, qualifies the removal of a cleanout plug, its replacement with a male adapter, and the subsequent extension of piping to a new fixture?

Never
When approved by a code enforcement officer and another cleanout is provided to replace the one being used as a connection point of drainage piping for a new fixture. (Correct answer)
When approved by the master plumber who has been issued a plumbing permit
When another cleanout is provided

Correct answer: When approved by a code enforcement officer and another cleanout is provided to replace the one being used as a connection point of drainage piping for a new fixture.

Unless the connection is authorized by a code officer and a new cleanout is provided to replace the cleanout being converted to a connection point for drainage piping, fittings housing cleanout plugs are not permitted to be utilized as a connection point for a drainage pipe that will feed a new fixture.

Question 20: When installing an ADA-compliant grab bar on the side wall of a water closet, what is the minimum required length of the grab bar?

36 inches
24 inches
48 inches
42 inches (Correct answer)

Correct answer: 42 inches

According to the Americans with Disabilities Act (ADA) Standards for Accessible Design, the side wall grab bar next to a water closet must be at least 42 inches long. It should be located a maximum of 12 inches from the rear wall and extend at least 54 inches from the rear wall.

Question 21: In a standard plumbing isometric drawing, a pipe is shown running horizontally on the page at a 30-degree angle. The line then turns at a 90-degree elbow symbol, and the continuing pipe is drawn as a perfectly vertical line on the page. What does this vertical line represent?

A pipe installed at a 45-degree horizontal angle.
A vertical pipe rising up or dropping down. (Correct answer)
A flexible connector transitioning between floors.
A horizontal pipe running perpendicular to the original pipe.

Correct answer: A vertical pipe rising up or dropping down.

Isometric drawings use specific conventions to represent a 3D system on a 2D page. Horizontal pipes are drawn at 30-degree angles to the horizontal, while pipes that are physically vertical in the installation are always drawn as vertical lines on the page.

Question 22: A commercial kitchen is installing a new chemical dispensing unit that connects directly to the potable water supply to mix cleaning solutions. This is considered a high-hazard application. Which of the following backflow prevention devices is required for this installation?

Double Check Valve Assembly (DCVA)
Atmospheric Vacuum Breaker (AVB)
Pressure Vacuum Breaker (PVB)
Reduced Pressure Zone Assembly (RPZ) (Correct answer)

Correct answer: Reduced Pressure Zone Assembly (RPZ)

A Reduced Pressure Zone (RPZ) assembly provides the highest level of protection and is required for high-hazard applications where contaminants like cleaning chemicals could cause illness or death if they enter the potable water system. A DCVA is for low-hazard situations, while AVBs and PVBs only protect against back-siphonage, not back-pressure.

Question 23: Which of the following is a code-compliant method for connecting a domestic dishwasher's drainage hose to the sanitary drainage system to prevent backflow?

A direct connection to the garbage disposal's inlet.
A P-trap installed exclusively for the dishwasher.
A simple loop in the drain hose below the sink rim.
An approved air gap fitting installed on the countertop. (Correct answer)

Correct answer: An approved air gap fitting installed on the countertop.

Most plumbing codes mandate that a domestic dishwasher must discharge through an approved air gap fitting to prevent contaminated water from the sink or drainage system from siphoning back into the dishwasher. The air gap provides a physical separation, making it a reliable backflow prevention method. While some jurisdictions may allow a high loop as an alternative, the air gap is the specifically listed and most protective device.

Question 24: Which of the following is the primary purpose of a vent in a drainage system?

To equalize pressure and protect trap seals (Correct answer)
To provide a means of cleaning the drain line
To increase the velocity of the wastewater
To filter out solid waste materials

Correct answer: To equalize pressure and protect trap seals

The primary function of a vent system is to introduce air into the drainage pipes. This equalizes the atmospheric pressure within the system, preventing the siphoning of trap seals and allowing wastewater to flow freely by gravity.

Question 25: A plumber needs to connect a horizontal branch drain to a vertical stack. To ensure proper flow and prevent blockages, which type of fitting is most appropriate for this connection?

A combination wye and 1/8 bend or a long sweep fitting (Correct answer)
A short sweep 90-degree elbow
A vent tee
A sanitary tee

Correct answer: A combination wye and 1/8 bend or a long sweep fitting

When transitioning from a horizontal drain to a vertical stack, it is critical to use fittings that promote a smooth, sweeping change in direction. A combination wye and 1/8 bend (or a long sweep fitting) is required to prevent solids from building up at the change of direction, which can occur with the sharper turn of a sanitary tee. Sanitary tees are typically used for vertical to horizontal transitions.

Question 26: Which of the following methods cannot be used to test gas pipeline installations?

Oxygen (Correct answer)
Nitrogen
Carbon dioxide
Air

Correct answer: Oxygen

Before any repair is done on an existing sewage or water line, a code enforcement agency frequently wants a site plan and specifications on file. The intended placement for new piping should be shown on the site plan, as well as the location of any existing piping.

Question 27: An isometric drawing shows a rolling offset where a vent pipe rises 15 inches vertically and offsets 20 inches horizontally, using 45-degree fittings. What is the center-to-center length of the travel pipe required for this offset?

49.49 inches
35.35 inches (Correct answer)
25.00 inches
28.28 inches

Correct answer: 35.35 inches

This requires a two-step calculation. First, find the 'true offset' using the Pythagorean theorem (a² + b² = c²), where 'a' is the rise and 'b' is the horizontal offset. True Offset = √(15² + 20²) = √(225 + 400) = √625 = 25 inches. Second, calculate the travel piece by multiplying the true offset by the 45-degree constant: 25" × 1.414 = 35.35 inches.

Question 28: Which of the following locations would specifically require the installation of a water hammer arrestor according to most modern plumbing codes?

At the connection to an outdoor hose bibb
On the water supply lines for a clothes washing machine (Correct answer)
At the highest point in the water distribution system
On the hot water supply line to a kitchen sink

Correct answer: On the water supply lines for a clothes washing machine

Water hammer is caused by the sudden stoppage of water flow, creating a shockwave. Modern codes require water hammer arrestors to be installed near any quick-closing valves. The solenoid valves in a clothes washing machine are a prime example of quick-closing valves, making arrestors mandatory on both the hot and cold supply lines to prevent damage to the pipes.

Question 29: Under IPC, what is the minimum vent pipe diameter allowed?

1-1/2 inches
2 inches
1 inch
1-1/4 inches (Correct answer)

Correct answer: 1-1/4 inches

The IPC sets 1-1/4 inches as the minimum diameter for any vent pipe.

Question 30: In a plumbing isometric drawing, a vertical drain stack changes to a horizontal run. Which of the following fittings is typically used for this transition to ensure proper flow?

A sanitary tee laid on its back
A standard short-radius 90-degree elbow
A vent tee
A long sweep 90-degree elbow or a combination wye and 1/8 bend (Correct answer)

Correct answer: A long sweep 90-degree elbow or a combination wye and 1/8 bend

For a change of direction from vertical to horizontal in a drainage system, codes require a fitting that has a longer radius to prevent solids from stopping and causing a blockage. A long sweep 90-degree elbow or a combination wye and 1/8 bend provides a smoother transition for the waste flow compared to a standard short-radius elbow or a sanitary tee on its back.

Question 31: A plumber is installing a gas-fired water heater with a bottom ignition source in a residential garage. According to most plumbing codes, what is the minimum required elevation of the ignition source above the garage floor?

18 inches (Correct answer)
6 inches
24 inches
12 inches

Correct answer: 18 inches

To prevent the ignition of flammable vapors (such as gasoline or solvent fumes) that are heavier than air and can accumulate near the floor, plumbing and mechanical codes require the ignition source of fuel-fired appliances to be elevated. The standard minimum height is 18 inches above the floor in locations like a garage.

Question 32: What is the federally mandated maximum flow rate for a standard showerhead manufactured after 1994, according to the Energy Policy Act?

3.0 GPM at 60 psi
2.5 GPM at 80 psi (Correct answer)
1.8 GPM at 80 psi
2.0 GPM at 80 psi

Correct answer: 2.5 GPM at 80 psi

The U.S. Energy Policy Act of 1992 (effective 1994) set the national maximum flow rate for showerheads at 2.5 gallons per minute (GPM) when tested at a pressure of 80 pounds per square inch (psi). While some states and programs like WaterSense have adopted lower rates, 2.5 GPM remains the federal standard.

Question 33: A plumber pressurizes a newly installed gas piping system for a leak test. For a typical residential system tested with air, what is the common minimum test pressure and duration required by code?

50 psi for 30 minutes
5 psi for 10 minutes
Working pressure for 24 hours
10 psi for 15 minutes (Correct answer)

Correct answer: 10 psi for 15 minutes

Most plumbing and fuel gas codes require that a new gas piping system be subjected to a pressure test before being put into service. For a typical residential system, the test pressure must be at least 10 psi, and it must hold this pressure for a minimum of 15 minutes without any drop. The gauge used must be appropriate for this pressure range, typically with 1/10 psi increments.

Question 34: To properly size a water supply system, a plumber uses the Water Supply Fixture Unit (WSFU) method. Which of the following best describes the principle behind this method?

It assigns a weight to each fixture based on its water consumption, duration of use, and frequency of use to determine the probable peak demand. (Correct answer)
It calculates the peak water demand assuming all fixtures are used simultaneously.
It determines the pipe size based solely on the total number of fixtures in the building, regardless of type.
It measures the static pressure required to operate the most demanding fixture in the system.

Correct answer: It assigns a weight to each fixture based on its water consumption, duration of use, and frequency of use to determine the probable peak demand.

The Water Supply Fixture Unit (WSFU) method, developed by Roy B. Hunter, is based on the theory of probability. It recognizes that not all fixtures will be used at the same time. Each fixture is assigned a WSFU value that represents its load-producing characteristics (water consumption, duration, and frequency of use), and these values are summed to estimate the peak probable demand on the system.

Question 35: Under IPC, what is the maximum developed length of a trap arm (from trap weir to vent) for a 1-1/2 inch pipe?

5 feet (Correct answer)
8 feet
3 feet
6 feet

Correct answer: 5 feet

The IPC allows a maximum trap arm length of 5 feet for a 1-1/2 inch pipe.

Question 36: A plumber has a travel piece that is 35 inches long and was installed using two 45-degree fittings. What is the offset distance between the centerlines of the two parallel pipes?

35 inches
24.75 inches (Correct answer)
17.5 inches
49.5 inches

Correct answer: 24.75 inches

To find the offset when the travel length is known, you multiply the travel by 0.707 (the reciprocal of 1.414) or divide the travel by 1.414. Calculation: 35 inches * 0.707 = 24.745 inches, which rounds to 24.75 inches.

Question 37: A plumber is installing a natural gas piping system for a new residential furnace. According to most fuel gas codes, which of the following is a mandatory requirement for the piping installation just before the final connection to the furnace?

A flexible appliance connector must be used for the final 3 feet of the connection.
The piping must be painted yellow for identification purposes throughout its entire length.
The gas pipe must be electrically bonded to the cold water piping within 1 foot of the appliance.
A sediment trap must be installed downstream of the appliance shutoff valve and as close to the appliance inlet as practical. (Correct answer)

Correct answer: A sediment trap must be installed downstream of the appliance shutoff valve and as close to the appliance inlet as practical.

Most fuel gas codes, such as the IFGC and NFPA 54, require a sediment trap (also known as a drip leg or dirt leg) to be installed downstream of the appliance's shutoff valve. This device is designed to collect any sediment, debris, or moisture that may be in the gas line, preventing it from entering and damaging the appliance's sensitive gas controls. The trap is typically constructed with a tee fitting, a nipple at least 3 inches long, and a cap on the bottom.

Question 38: What is the minimum diameter of the discharge pipe for a T&P relief valve on a residential storage water heater?

1 inch
1/2 inch
3/4 inch (Correct answer)
3/8 inch

Correct answer: 3/4 inch

The T&P relief valve discharge pipe must be at least 3/4 inch in diameter, matching the standard relief valve outlet size, and must not be reduced in size throughout its length.

Question 39: When performing a water test on a newly installed DWV (Drain, Waste, and Vent) system, what is the minimum required head of water that must be applied to the system and for what duration, according to the IPC?

The system must be filled to the point of overflow for 5 minutes.
5 feet of head for 10 minutes.
A head equal to a 2-story building (approx. 20 feet) for 30 minutes.
10 feet of head for 15 minutes. (Correct answer)

Correct answer: 10 feet of head for 15 minutes.

According to IPC Section 312.2, a water test on a DWV system requires it to be subjected to not less than a 10-foot head of water. This pressure must be held for a minimum of 15 minutes without any evidence of leakage.

Question 40: A plumber is installing an island sink in a kitchen where a conventional vent through a wall is not feasible. Which of the following specialty vents is specifically designed for this application to prevent trap siphonage?

Island Fixture Vent (Loop Vent) (Correct answer)
Circuit Vent
Air Admittance Valve
Common Vent

Correct answer: Island Fixture Vent (Loop Vent)

An Island Fixture Vent, also known as a loop vent, is a code-approved method for venting fixtures that are not adjacent to a wall. It works by extending the vent up as high as possible under the counter, looping it over, and then running it down to connect to a horizontal drain that is itself vented elsewhere, effectively protecting the trap seal from siphonage.

Question 41: A plumber is installing a new natural gas piping system that will operate at a standard pressure of 7 inches water column (approx. 0.25 psi). According to the International Fuel Gas Code (IFGC), what is the minimum required air pressure test for this new installation?

0.5 psig for a minimum of 30 minutes
10 psig for a minimum of 5 minutes
3 psig for a minimum of 10 minutes (Correct answer)
1.5 times the operating pressure for 15 minutes

Correct answer: 3 psig for a minimum of 10 minutes

According to IFGC section 406.4.1, for a gas system with a proposed maximum working pressure less than or equal to 0.5 psi, the test pressure must be no less than 1.5 times the working pressure, but not less than 3 psig. The test duration must be a minimum of 10 minutes.

Question 42: A plumber is installing a drain line with a simple horizontal offset of 24 inches using 45-degree fittings. What is the required center-to-center length of the travel piece?

33.94 inches (Correct answer)
16.97 inches
24.00 inches
48.00 inches

Correct answer: 33.94 inches

To calculate the length of the travel piece in a 45-degree offset, the formula is Travel = Run × 1.414. Given a run (the offset distance) of 24 inches, the calculation is 24" × 1.414 = 33.936", which rounds to 33.94 inches.

Question 43: A plumber is installing a water closet in a residential bathroom. According to most model plumbing codes, what is the minimum required clearance from the centerline of the water closet to any side wall or partition?

12 inches
18 inches
15 inches (Correct answer)
21 inches

Correct answer: 15 inches

Most plumbing codes, including the International Plumbing Code (IPC) and Uniform Plumbing Code (UPC), mandate a minimum of 15 inches from the centerline of a water closet to any adjacent wall, partition, or vanity. This ensures adequate space for use and cleaning.

Question 44: What is the purpose of the dip tube in a storage tank water heater?

To prevent backflow into the cold supply line
To drain sediment from the bottom of the tank
To direct incoming cold water to the bottom of the tank (Correct answer)
To measure the internal water temperature

Correct answer: To direct incoming cold water to the bottom of the tank

The dip tube directs incoming cold water to the bottom of the tank so it does not mix with the hot water at the top, ensuring efficient delivery of hot water.

Question 45: Which of the following best describes a 'critical level' (CL) marking on a backflow prevention device?

The flood level of the fixture it protects
The maximum water pressure rating of the device
The minimum flow rate required for the device to operate
The level below which the device must not be installed to prevent backsiphonage (Correct answer)

Correct answer: The level below which the device must not be installed to prevent backsiphonage

The CL mark indicates the lowest point of installation to ensure the device functions correctly and prevents back-siphonage.

Question 46: A horizontal drainage line that is 48 feet long must be installed with a uniform grade of 1/8 inch per foot. What is the total fall of the pipe from its starting point to its end point?

4 inches
6 inches (Correct answer)
12 inches
8 inches

Correct answer: 6 inches

To calculate the total fall, multiply the length of the pipe run by the required grade per foot. Calculation: 48 feet * (1/8 inch/foot) = 6 inches.

Question 47: To comply with the Americans with Disabilities Act (ADA) standards, what is the maximum height the rim of a lavatory or sink can be mounted above the finished floor?

36 inches
32 inches
30 inches
34 inches (Correct answer)

Correct answer: 34 inches

ADA guidelines require that the rim or counter surface of a lavatory or sink be no more than 34 inches above the finished floor to ensure it is accessible to individuals using a wheelchair.

Question 48: Which of the following is the correct mathematical constant used to calculate the 'travel' piece when the 'set' of a 60-degree offset is known?

1.155 (Correct answer)
1.414
1.732
2.613

Correct answer: 1.155

The constant for calculating the travel of a 60-degree offset is 1.155. The formula is: Travel = Set x 1.155. The constant 1.414 is for 45-degree offsets, and 2.613 is for 22.5-degree offsets.

Question 49: According to most plumbing codes, what is the required range for a fixture trap's liquid seal depth?

2 inches to 4 inches (Correct answer)
1 inch to 3 inches
4 inches to 6 inches
3 inches to 5 inches

Correct answer: 2 inches to 4 inches

A trap seal between 2 and 4 inches is required to effectively block sewer gases while preventing siphonage or sluggish flow. A seal less than 2 inches is prone to evaporation or being siphoned out, and a seal deeper than 4 inches can slow drainage and lead to blockages.

Question 50: Per IPC, what is the minimum number of plumbing fixtures required for a business occupancy with 1–15 employees?

1 water closet, 1 lavatory (Correct answer)
1 water closet only
2 water closets, 2 lavatories
1 lavatory only

Correct answer: 1 water closet, 1 lavatory

IPC Table 403.1 requires at least 1 water closet and 1 lavatory for occupancies with 1–15 employees.

Question 51: A plumber is installing a 4-inch horizontal building drain that makes a single 90-degree turn. Which of the following statements about cleanout requirements is correct according to most plumbing codes?

A cleanout is only required if the total length of the drain exceeds 100 feet.
A cleanout is not required if a fixture with a removable trap is located within 5 feet of the turn.
A cleanout can be omitted if two 45-degree fittings are used to make the turn.
A cleanout is required at each change of direction greater than 45 degrees. (Correct answer)

Correct answer: A cleanout is required at each change of direction greater than 45 degrees.

Plumbing codes, such as the IPC Section 708.1.4, mandate the installation of cleanouts to allow access for clearing blockages. For horizontal drainage pipes, a cleanout is explicitly required at each change of direction that is greater than 45 degrees.

Question 52: A horizontal drainage pipe that is 48 feet long must be installed with a uniform grade of 1/4 inch per foot. What is the total fall of the pipe from its highest point to its lowest point?

8 inches
24 inches
6 inches
12 inches (Correct answer)

Correct answer: 12 inches

The total fall is calculated by multiplying the length of the pipe in feet by the required grade in inches per foot. Calculation: 48 feet * (1/4 inch/foot) = 12 inches.

Question 53: What is the minimum height above finished grade for the installation of an air admittance valve (AAV) in a crawl space?

4 inches (Correct answer)
6 inches
12 inches
2 inches

Correct answer: 4 inches

AAVs installed in crawl spaces must be located at least 4 inches above the insulation or other materials in the crawl space to ensure proper air access.

Question 54: What is the minimum required clearance in front of a cleanout for a 3-inch drain pipe to allow for proper rodding and servicing?

36 inches
18 inches (Correct answer)
24 inches
12 inches

Correct answer: 18 inches

The International Plumbing Code (IPC) specifies that cleanouts on 6-inch and smaller pipes must have a clearance of not less than 18 inches for rodding. The Uniform Plumbing Code (UPC) has similar requirements, stating that pipes over 2 inches need at least 24 inches, but 18 inches is a widely accepted minimum for smaller pipes.

Question 55: Which of the following must be preserved for a water service?

Tampering
Geothermal shifting due to seismic action
Vandalism
Damage during or related to backfilling of the water service trench (Correct answer)

Correct answer: Damage during or related to backfilling of the water service trench

A water service pipe needs to be buried below the area's frost line in order to prevent freezing. In order to prevent floating, the pipe must also be secured from floods. To prevent damage to the piping from occurring under the weight of the backfill material and settlement movement, the backfill must be clean and devoid of sharp items when backfilling a ditch that contains a water service.

Question 56: What is the shortest possible distance that a department store employee should have to travel to use the restroom?

500 feet (Correct answer)
250 feet
375 feet
100 feet

Correct answer: 500 feet

The distance that employees must go to access appropriate bathroom facilities cannot exceed 500 feet. They won't have to climb more than one set of steps during this stroll. Under these circumstances, bathrooms cannot be built more than one floor above the workspace. Buildings that house factory or industrial workers may be exempt from this rule. The normal guideline is the 500-foot rule, but you should verify your local ordinance to make sure.

Question 57: In a commercial building, a floor drain is located in a mechanical room that is rarely used, making the trap seal subject to evaporation. Which device is required to maintain the trap seal?

An air admittance valve
A trap primer (Correct answer)
A check valve
A vacuum breaker

Correct answer: A trap primer

A trap primer is a device that automatically supplies a small amount of water to a trap that is subject to losing its seal through evaporation, such as an infrequently used floor drain. This maintains the water seal, which is necessary to prevent sewer gases from entering the building.

Question 58: A plumber is installing water lines for a battery of washing machines in a laundromat. These machines have quick-closing solenoid valves. To prevent damage to the piping, which device is required?

Water hammer arrestors (Correct answer)
An expansion tank
A tempering valve
A check valve on each supply line

Correct answer: Water hammer arrestors

Fixtures with quick-closing valves, such as washing machines and dishwashers, can cause a sudden stop in water flow, creating a hydraulic shock wave known as water hammer. Plumbing codes require the installation of water hammer arrestors to absorb this shock and prevent damage to pipes, valves, and fixtures.

Question 59: When installing Corrugated Stainless Steel Tubing (CSST) for a natural gas system, what specific safety measure is mandated by the manufacturer and fuel gas codes to protect against electrical hazards?

Wrapping the entire length of tubing in an approved insulating tape.
Ensuring the CSST is installed with at least 6 inches of separation from all electrical wiring.
Installing a dielectric union at the connection to every appliance.
Bonding the CSST system directly to the building's electrical service grounding electrode system. (Correct answer)

Correct answer: Bonding the CSST system directly to the building's electrical service grounding electrode system.

To mitigate the risk of damage from electrical arcing (such as from a nearby lightning strike), CSST systems must be bonded to the building's electrical service grounding electrode system. This is typically accomplished with a minimum 6 AWG copper wire and a proper bonding clamp attached to a rigid pipe component or CSST fitting.

Question 60: When performing a material take-off from a detailed isometric drawing, a dimension line indicates a pipe length of 6'-2" between the symbols for two fittings. What does this measurement typically represent?

The distance from the face of one fitting to the face of the next fitting.
The overall length of the assembly, including the fittings themselves.
The distance from the center of one fitting to the center of the next fitting. (Correct answer)
The exact cut length of the pipe required for fabrication.

Correct answer: The distance from the center of one fitting to the center of the next fitting.

In plumbing isometric drawings, dimensions are almost always given from the center of one fitting to the center of the next. The plumber must then calculate the actual 'cut length' of the pipe by subtracting the fitting allowances (the distance from the center of the fitting to the face where the pipe seats).

Question 61: A high-efficiency condensing gas furnace is being installed. This appliance operates with a positive vent static pressure and produces acidic condensate. To which venting category does this appliance belong?

Category III
Category IV (Correct answer)
Category I
Category II

Correct answer: Category IV

Gas appliances are classified into four venting categories. Category IV appliances operate with a positive vent static pressure (fan-assisted) and have a low vent gas temperature that causes condensation. The vent must be airtight, watertight, and constructed of corrosion-resistant material like PVC or stainless steel, as specified by the manufacturer.

Question 62: Which of the following best describes a "rolling offset" as it would be depicted in an isometric plumbing drawing?

A pipe that changes direction in two planes simultaneously, such as both vertically and horizontally. (Correct answer)
A single 90-degree fitting used to change the pipe's direction horizontally.
Two 90-degree fittings used to bypass a vertical obstruction in the same plane.
A U-shaped assembly of pipes used to create a P-trap seal.

Correct answer: A pipe that changes direction in two planes simultaneously, such as both vertically and horizontally.

A rolling offset is a compound turn used when a pipe needs to move around an obstruction by changing its path in two planes at the same time (e.g., moving up and to the left). It is typically constructed using two angled fittings, like 45-degree elbows, to achieve the change in both horizontal and vertical direction.

Question 63: Under the IPC, the maximum water pressure at any fixture in a building shall not exceed:

100 psi
120 psi
80 psi (Correct answer)
60 psi

Correct answer: 80 psi

The IPC sets 80 psi as the maximum allowable water pressure at any fixture; a pressure reducing valve must be installed if supply exceeds this.

Question 64: When installing a water service line, what is the general code requirement for the minimum horizontal separation distance between the potable water line and a sanitary sewer line in the same trench?

A minimum of 18 inches is required, regardless of pipe material.
The pipes must be separated by at least 5 feet of undisturbed earth.
The water line must be placed on a shelf 12 inches above the sewer line. (Correct answer)
There is no minimum separation if the sewer pipe is cast iron.

Correct answer: The water line must be placed on a shelf 12 inches above the sewer line.

To prevent contamination of the potable water supply in case of a leak, plumbing codes mandate specific separation requirements. The most common rule is that if the water line and sewer line are in the same trench, the water line must be placed on a solid shelf of earth at least 12 inches above the top of the sewer line. If they are at the same elevation, a much greater horizontal separation is required.

Question 65: When creating an offset using two 60-degree fittings, the distance between the centerlines of the parallel pipes is 15 inches. What is the approximate length of the travel pipe required between the fittings?

21.2 inches
17.3 inches (Correct answer)
15.0 inches
30.0 inches

Correct answer: 17.3 inches

The constant for a 60-degree offset is 1.155. The travel is calculated by multiplying the offset (15 inches) by 1.155, which equals 17.325 inches.

Question 66: According to most model plumbing codes, what is the minimum height a vent pipe must terminate above a roof surface?

2 inches
4 inches
6 inches (Correct answer)
12 inches

Correct answer: 6 inches

Most model plumbing codes, including the International Plumbing Code (IPC), require a vent to terminate at least 6 inches above the roof surface. This height helps prevent the vent from being blocked by snow or debris and allows sewer gases to disperse safely. In areas with heavy snowfall, this height requirement may be increased.

Question 67: Which of the following tools can be used to enhance water pressure when a water source's pressure is insufficient for a plumbing system's requirements?

All of the above
None of the above
A booster pump (Correct answer)
A pressure increasing valve

Correct answer: A booster pump

To boost water pressure as needed, booster pumps can be installed. As a component of the water distribution system, these pumps are placed. These pumps have the capacity to decrease volume to boost pressure without impairing the functionality of plumbing fixtures.

Question 68: An atmospheric vacuum breaker (AVB) is installed on a utility sink faucet to prevent back-siphonage. Which of the following is a critical installation requirement for this device to function correctly?

It is effective against both back-siphonage and backpressure.
It can be subjected to continuous pressure for up to 24 hours.
It must be installed with a shutoff valve downstream of the device.
It must be installed at least 6 inches above the flood-level rim of the fixture. (Correct answer)

Correct answer: It must be installed at least 6 inches above the flood-level rim of the fixture.

An Atmospheric Vacuum Breaker (AVB) works by allowing air to enter and break a siphon. For it to function properly, it must be installed at least 6 inches above the flood-level rim of the fixture or the highest outlet it serves. It cannot be under continuous pressure and cannot have any shutoff valves downstream, as this would prevent it from opening to the atmosphere.

Question 69: Which of the following describes the minimum required length for a trap arm, as measured from the trap weir to the inner edge of the vent?

It must be equal to the diameter of the trap arm.
It must be at least two times the diameter of the trap arm. (Correct answer)
It must not exceed the diameter of the trap arm.
It must be at least 12 inches long.

Correct answer: It must be at least two times the diameter of the trap arm.

To prevent crown-venting, where the vent opening becomes fouled by waste, and to ensure proper function, the trap arm must have a minimum length. The code specifies this minimum length to be no less than two times the nominal pipe diameter of the trap arm itself.

Question 70: Which type of valve is required to be installed on the water supply to a water heater to allow for servicing?

Pressure reducing valve
Backflow preventer
Gate valve or full-port ball valve (Correct answer)
Check valve

Correct answer: Gate valve or full-port ball valve

A gate valve or full-port ball valve must be installed on the cold water supply to a water heater to allow isolation for service.

Question 71: A plumber needs to cut a piece of copper pipe to connect two 90-degree wrought copper elbows. The center-to-center measurement between where the fittings will be is 36 inches. The fitting allowance (take-off) for each elbow is 3/4 inch. What is the required end-to-end cut length of the pipe?

35 1/4 inches
34 1/2 inches (Correct answer)
37 1/2 inches
36 inches

Correct answer: 34 1/2 inches

To find the cut length of the pipe, the take-off for both fittings must be subtracted from the center-to-center measurement. The pipe fits into the sockets of the fittings. Calculation: 36" - (3/4" + 3/4") = 36" - 1 1/2" = 34 1/2 inches.

Question 72: Healthcare facilities are required to have ice producers and ice storage chests installed ___________

in a nurse station or other similarly supervised area (Correct answer)
in locked rooms
in rooms that are clearly labeled as containing ice in the event that it is need for burn victims
adjacent to the kitchen area

Correct answer: in a nurse station or other similarly supervised area

In healthcare facilities, ice machines and ice storage chests must be placed in nurse stations or other locations under comparable monitoring. Equipment for making and storing ice must be kept away from contaminated areas. Every ice facility must be secure and sanitary.

Question 73: The plumbing that transports potable water from a water source to a water distribution system is referred to as which of the following?

Either water main and water supply (Correct answer)
Water main
None of the above
Water supply

Correct answer: Either water main and water supply

A water main or a water supply is the main conduit that transports potable water to a water-distribution system. Regardless of whether the water is flowing from a municipal water system or a water well, this is the situation. A water supply pipe must have a minimum diameter of.75 inches.

Question 74: Which of the following materials is NOT approved for potable water supply piping under the IPC?

PEX tubing
ABS pipe (Correct answer)
CPVC
Type L copper

Correct answer: ABS pipe

ABS (acrylonitrile butadiene styrene) is a drain-waste-vent material and is not approved for potable water supply piping.

Question 75: A journeyman plumber is installing a Corrugated Stainless Steel Tubing (CSST) gas line in a new residential construction. What is a critical safety requirement regarding the bonding of this piping system?

A bonding clamp must be attached directly to the corrugated portion of the tubing.
The system must be bonded to the electrical service grounding system with a #10 AWG copper wire.
The CSST itself must be used as the grounding electrode.
The system must be bonded to the electrical service grounding system with a conductor no smaller than a #6 AWG copper wire. (Correct answer)

Correct answer: The system must be bonded to the electrical service grounding system with a conductor no smaller than a #6 AWG copper wire.

To mitigate the risk of damage from an indirect lightning strike, both the National Fuel Gas Code and manufacturers' instructions require CSST to be bonded to the building's electrical service grounding system. This bonding jumper must be a copper wire no smaller than 6 AWG or its equivalent. The clamp should not be attached directly to the corrugated tubing itself but rather to a rigid pipe component or the CSST fitting.

Question 76: A plumber is connecting a lavatory drain to the p-trap. The component that connects the fixture's drain outlet to the trap is known as a:

Continuous waste
Trap arm
Tailpiece (Correct answer)
Escutcheon

Correct answer: Tailpiece

A tailpiece is the straight section of pipe that connects the sink's strainer or drain outlet directly to the inlet of the p-trap. It is a critical fitting for completing the fixture's drainage assembly.

Question 77: What type of backflow is caused by a negative or sub-atmospheric pressure in the water supply piping, often resulting from a water main break or firefighting activities nearby?

Back-pressure
Hydraulic shock
Back-siphonage (Correct answer)
Cross-contamination

Correct answer: Back-siphonage

Back-siphonage is the reversal of flow caused by a reduction in system pressure, which creates a partial vacuum that can pull contaminants into the potable water supply. This is different from back-pressure, which occurs when downstream pressure is higher than the supply pressure.

Question 78: A journeyman plumber encounters an existing installation that does not comply with the current code but was legal when installed. This is known as:

A grandfathered or nonconforming installation (Correct answer)
A variance that must be renewed annually
A code violation requiring immediate correction
An illegal installation subject to fines

Correct answer: A grandfathered or nonconforming installation

Installations that were code-compliant when built but no longer meet current code are considered nonconforming (grandfathered) and are generally allowed to remain.

Question 79: According to the International Plumbing Code (IPC) and Uniform Plumbing Code (UPC), what is the acceptable range for a fixture trap's water seal depth?

3 inches to 5 inches
2 inches to 4 inches (Correct answer)
4 inches to 6 inches
1 inch to 3 inches

Correct answer: 2 inches to 4 inches

Plumbing codes specify that a standard trap seal must be between 2 and 4 inches deep. A seal less than 2 inches is susceptible to evaporation or being siphoned, while a seal deeper than 4 inches can slow drainage and lead to blockages.

Question 80: A plumber is analyzing an isometric drawing for a drain line that requires a 45-degree offset. The drawing shows the offset distance (the center-to-center distance between the parallel pipes) is 24 inches. What is the required travel, or true length, of the pipe between the two 45-degree fittings?

28.8 inches
48.0 inches
33.9 inches (Correct answer)
24.0 inches

Correct answer: 33.9 inches

The formula to calculate the travel piece for a 45-degree offset is: Travel = Offset × 1.414. In this scenario, 24 inches × 1.414 = 33.936 inches, which is rounded to 33.9 inches. This constant is derived from the properties of a 45-45-90 triangle.

Question 81: It is necessary for sewage pumps or sumps used to store sewage to be ________.

Covered with a gas-tight cover
Both "vented" and "covered with a gas-tight cover" (Correct answer)
Placed outside of any habitable structure
Vented

Correct answer: Both "vented" and "covered with a gas-tight cover"

It is necessary to vent sump sewage pumps that remove sanitary waste to the outside air. If a pneumatic sewer ejector pump is to be installed, the vent cannot be connected to a general venting system. The vent can be connected back to a common venting system when a standard sewer pump is to be used. A vent for a sewage sump will typically need to have a minimum diameter of two inches. Sewage sump coverings, in addition to effective venting, must be gas-tight.

Journeyman Plumber Exam

The Journeyman Plumber Exam exam validates essential knowledge and skills required for certification or licensure in this field.

Questions

120 min

Time Limit

70%

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These practice questions were written with AI tools. They are not real exam questions. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy

Sources & references

Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy

tsbpe.texas.gov — Test delivery, fees, score release, eligibility, renewal · verified Oct 2026
pearsonvue.com — Exam format, passing score, retake policy, score validity · verified Oct 2026