Backflow Exam Study Guide
2026/2027 Accurate Questions
with Correct Detailed Solutions ||
100% Guaranteed Pass Newest
Version
Description: A comprehensive 200-question multiple-choice revision set covering
backflow prevention theory, hydraulics, cross-connection control, test procedures,
codes, and device-specific knowledge. Keywords: backflow, cross-connection, RPZ,
DCVA, PVB, SVB, AVB, air gap, backpressure, backsiphonage, ASSE, USC, test kit,
certification.
1. What is the primary purpose of a backflow prevention assembly?
A. Increase water pressure
B. Prevent contamination of the potable water supply ✅
C. Filter sediment from water
D. Regulate water temperature
2. Backflow is best defined as:
A. Normal forward flow of water
B. Reverse flow of water or other substances into the potable supply ✅
C. Water hammer in pipes
D. Loss of pressure in a main
,3. Which two conditions cause backflow?
A. Backpressure and backsiphonage ✅
B. Cavitation and turbulence
C. Friction and velocity
D. Osmosis and diffusion
4. Backsiphonage is caused by:
A. An increase in supply pressure
B. A negative or sub-atmospheric pressure in the supply line ✅
C. A pump adding pressure downstream
D. Thermal expansion
5. Backpressure occurs when:
A. Supply pressure drops below zero
B. Downstream pressure exceeds supply pressure ✅
C. A vacuum forms in the main
D. The meter fails
6. A cross-connection is:
A. Any pipe crossing another pipe
B. Any actual or potential connection between potable and non-potable systems ✅
C. A plumbing vent
D. A water meter bypass
7. Which is an example of a direct cross-connection?
A. A hose bib with a vacuum breaker
B. A submerged inlet in a chemical tank ✅
C. An air gap
D. A reduced pressure zone assembly
8. An indirect cross-connection may occur through:
A. A physical pipe connection
B. A submerged outlet subject to backpressure or backsiphonage ✅
,C. A closed valve
D. A check valve only
9. The degree of hazard posed by a cross-connection depends on:
A. Pipe size only
B. The contaminant and the likelihood of backflow ✅
C. Water temperature only
D. The color of the pipe
10. A "health hazard" cross-connection involves:
A. Aesthetic problems only
B. Contaminants that could cause illness or death ✅
C. Slight discoloration
D. Taste and odor issues only
11. A "non-health hazard" cross-connection involves:
A. Toxic chemicals
B. Contaminants that affect aesthetics but not health ✅
C. Radioactive material
D. Sewage
12. The most reliable method of backflow prevention is:
A. Double check valve assembly
B. Air gap ✅
C. Pressure vacuum breaker
D. Atmospheric vacuum breaker
13. An air gap must have a minimum separation of:
A. One pipe diameter
B. Two times the effective opening of the discharge pipe ✅
, C. 1 inch
D. 6 inches
14. The effective opening of a discharge pipe is:
A. Its outside diameter
B. Its inside diameter or the smallest cross-sectional area ✅
C. Its circumference
D. Its length
15. A reduced pressure zone (RPZ) assembly consists of:
A. Two check valves only
B. Two independently acting check valves and a differential relief valve ✅
C. One check valve and one air gap
D. One relief valve only
16. The relief valve on an RPZ opens when:
A. Supply pressure is normal
B. The pressure differential between the two check valves drops below a set point ✅
C. Flow stops
D. The first check valve fails closed
17. The RPZ is used for:
A. Low-hazard applications only
B. High-hazard applications ✅
C. Irrigation only
D. Fire sprinkler systems only
18. A double check valve assembly (DCVA) is used for:
A. High-hazard applications
B. Low-hazard applications ✅
C. Sewage lines
D. Steam lines
2026/2027 Accurate Questions
with Correct Detailed Solutions ||
100% Guaranteed Pass Newest
Version
Description: A comprehensive 200-question multiple-choice revision set covering
backflow prevention theory, hydraulics, cross-connection control, test procedures,
codes, and device-specific knowledge. Keywords: backflow, cross-connection, RPZ,
DCVA, PVB, SVB, AVB, air gap, backpressure, backsiphonage, ASSE, USC, test kit,
certification.
1. What is the primary purpose of a backflow prevention assembly?
A. Increase water pressure
B. Prevent contamination of the potable water supply ✅
C. Filter sediment from water
D. Regulate water temperature
2. Backflow is best defined as:
A. Normal forward flow of water
B. Reverse flow of water or other substances into the potable supply ✅
C. Water hammer in pipes
D. Loss of pressure in a main
,3. Which two conditions cause backflow?
A. Backpressure and backsiphonage ✅
B. Cavitation and turbulence
C. Friction and velocity
D. Osmosis and diffusion
4. Backsiphonage is caused by:
A. An increase in supply pressure
B. A negative or sub-atmospheric pressure in the supply line ✅
C. A pump adding pressure downstream
D. Thermal expansion
5. Backpressure occurs when:
A. Supply pressure drops below zero
B. Downstream pressure exceeds supply pressure ✅
C. A vacuum forms in the main
D. The meter fails
6. A cross-connection is:
A. Any pipe crossing another pipe
B. Any actual or potential connection between potable and non-potable systems ✅
C. A plumbing vent
D. A water meter bypass
7. Which is an example of a direct cross-connection?
A. A hose bib with a vacuum breaker
B. A submerged inlet in a chemical tank ✅
C. An air gap
D. A reduced pressure zone assembly
8. An indirect cross-connection may occur through:
A. A physical pipe connection
B. A submerged outlet subject to backpressure or backsiphonage ✅
,C. A closed valve
D. A check valve only
9. The degree of hazard posed by a cross-connection depends on:
A. Pipe size only
B. The contaminant and the likelihood of backflow ✅
C. Water temperature only
D. The color of the pipe
10. A "health hazard" cross-connection involves:
A. Aesthetic problems only
B. Contaminants that could cause illness or death ✅
C. Slight discoloration
D. Taste and odor issues only
11. A "non-health hazard" cross-connection involves:
A. Toxic chemicals
B. Contaminants that affect aesthetics but not health ✅
C. Radioactive material
D. Sewage
12. The most reliable method of backflow prevention is:
A. Double check valve assembly
B. Air gap ✅
C. Pressure vacuum breaker
D. Atmospheric vacuum breaker
13. An air gap must have a minimum separation of:
A. One pipe diameter
B. Two times the effective opening of the discharge pipe ✅
, C. 1 inch
D. 6 inches
14. The effective opening of a discharge pipe is:
A. Its outside diameter
B. Its inside diameter or the smallest cross-sectional area ✅
C. Its circumference
D. Its length
15. A reduced pressure zone (RPZ) assembly consists of:
A. Two check valves only
B. Two independently acting check valves and a differential relief valve ✅
C. One check valve and one air gap
D. One relief valve only
16. The relief valve on an RPZ opens when:
A. Supply pressure is normal
B. The pressure differential between the two check valves drops below a set point ✅
C. Flow stops
D. The first check valve fails closed
17. The RPZ is used for:
A. Low-hazard applications only
B. High-hazard applications ✅
C. Irrigation only
D. Fire sprinkler systems only
18. A double check valve assembly (DCVA) is used for:
A. High-hazard applications
B. Low-hazard applications ✅
C. Sewage lines
D. Steam lines
