What is backflow in a plumbing system?
Correct Answer
B) Undesired reversal of flow that can contaminate the potable water supply
Backflow is an undesired reversal of flow that can draw or push contaminants into potable water. Other choices describe drainage, HVAC air movement, or pressure shock.
Why This Is the Correct Answer
Backflow is an undesired reversal of flow that can draw or push contaminants into potable water. Other choices describe drainage, HVAC air movement, or pressure shock.
Why the Other Options Are Wrong
Option A: The normal flow from a fixture to a drain, leaving backflow unverified
The trap in A is The normal flow from a fixture to a drain. That selection is wrong because the option does not produce the required Backflow outcome, Undesired reversal of flow that can contaminate the potable water supply.
Option C: Airflow returning through a supply diffuser, leaving backflow unverified
Choice C (Airflow returning through a supply diffuser) is rejected because it answers the Backflow prompt with the wrong practical move.
Option D: Water hammer caused by a quick-closing valve
In mechanical and plumbing, Water hammer caused by a quick-closing valve is the wrong selection for Backflow: it leaves out the controlling Backflow result: Undesired reversal of flow that can contaminate the potable water supply.
Memory Technique
Attach backflow to a tag: remember the function, then the wording Undesired reversal of flow that can contaminate the potable water supply.
Reference Hint
Open Mechanical and Electrical Systems for Construction Managers, 4th Ed., 2024; use the index entry or section for "Plumbing backflow terminology" to confirm that Backflow is an undesired reversal of flow that can draw or push contaminants into potable water.
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