Journeyman Plumber 2 Exam Questions & Answers 2026 (1–10)

Question 1

What is the definition of 'backflow' in a plumbing system?

TheoryPractice · Accepted Answer

The reversal of normal flow direction in a piping system. Backflow is the undesirable reversal of flow in a piping system, which can allow contaminants to enter the potable water supply. Understanding this basic definition is foundational to cross-connection control.

Question 2

A cross-connection is best defined as which of the following?

TheoryPractice · Accepted Answer

Any physical link between a potable water system and any source of contamination. A cross-connection is any actual or potential link between the potable water supply and any source of pollution or contamination. Eliminating or protecting cross-connections is the goal of cross-connection control programs.

Question 3

Which term describes backflow caused by the downstream pressure exceeding the supply pressure?

TheoryPractice · Accepted Answer

Backpressure backflow. Backpressure backflow occurs when downstream pressure becomes greater than the supply (system) pressure, forcing contaminants backward into the potable supply. This can happen in boiler systems, pumped systems, or elevated piping.

Question 4

Back-siphonage is caused by which condition in the water supply system?

TheoryPractice · Accepted Answer

Negative pressure (vacuum) in the supply line. Back-siphonage is the backflow of potentially contaminated water caused by a negative pressure (partial vacuum) in the supply piping, similar to the siphon effect. It can occur during water main breaks or high-demand events.

Question 5

Which of the following correctly distinguishes a pollutant from a contaminant in cross-connection control?

TheoryPractice · Accepted Answer

A pollutant degrades water quality but may not pose an immediate health hazard, while a contaminant poses a direct health hazard. In cross-connection control, a pollutant creates an aesthetic nuisance or low-degree hazard (e.g., mineral deposits), whereas a contaminant creates an actual health hazard (e.g., pesticides, sewage). This distinction drives the level of backflow protection required.

Question 6

When classifying cross-connections, a 'high-hazard' connection involves which type of substance?

TheoryPractice · Accepted Answer

Substances that are toxic, pathogenic, or otherwise harmful to human health. A high-hazard cross-connection involves a substance that is toxic, pathogenic, or otherwise dangerous to health (e.g., chemicals, sewage). High-hazard connections require a higher degree of protection such as an air gap or reduced pressure principle (RP) assembly.

Question 7

A residential lawn irrigation system supplied by potable water and using chemical fertilizer injection would be classified as which hazard level?

TheoryPractice · Accepted Answer

High hazard — chemical injection creates a potential health hazard. The introduction of chemical fertilizers or pesticides through an injector connected to the potable supply creates a high-hazard cross-connection, regardless of the residential setting. This requires at minimum a reduced pressure principle backflow preventer.

Question 8

Which of the following connections would typically be classified as a LOW-hazard cross-connection?

TheoryPractice · Accepted Answer

A simple garden hose submerged in a bucket of clean, untreated water. A garden hose submerged in clean (non-chemical) water represents a low-hazard (pollution) cross-connection since the water itself poses minimal health risk, though back-siphonage protection is still required. The other options involve chemicals that elevate the hazard to high.

Question 9

An air gap is considered which type of backflow protection?

TheoryPractice · Accepted Answer

The highest degree of protection, providing a complete physical break in the pipeline. An air gap is an unobstructed vertical distance between the water outlet and the flood-level rim of a receiving vessel. It provides the highest degree of protection because it creates a complete physical separation — no mechanical failure can allow backflow.

Question 10

A Reduced Pressure Principle (RP) backflow preventer works by maintaining which condition?

TheoryPractice · Accepted Answer

A lower pressure in the relief zone than in both the supply and discharge zones. An RP assembly maintains a reduced-pressure zone between its two check valves. This zone is always at a lower pressure than the supply, ensuring that if either check fails, water flows out through the relief valve rather than backward into the supply.

Journeyman Plumber 2 Exam Questions & Answers 2026 (1–10)

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