Plumbing Systems - Question Practice Test - Answers at the Bottom
1. During an inspection, the water pressure at an exterior hose bibb measures 95 psi. What is the MOST appropriate concern?
A. The pressure is too low for normal fixtures
B. Excessive pressure can damage plumbing components and fixtures
C. The water heater will not operate
D. The main drain is obstructed
2. What is the primary purpose of a pressure-reducing valve (PRV) in a residential water supply system?
A. Increase water temperature
B. Reduce excessive incoming water pressure
C. Prevent sewer gases from entering the house
D. Increase drainage flow
3. An inspector observes greenish-blue staining around copper pipe fittings. This condition MOST commonly suggests:
A. Corrosion or previous leakage
B. Excessive drain slope
C. Improper venting
D. High water temperature only
4. When galvanized steel water-supply piping ages, which problem is commonly encountered?
A. The pipe diameter increases internally
B. Internal corrosion restricts water flow
C. The piping becomes electrically nonconductive
D. Water pressure always increases
5. What is the primary purpose of an anti-siphon or backflow-prevention device on an exterior hose connection?
A. Increase hose pressure
B. Prevent contaminated water from being drawn into the potable water supply
C. Drain the plumbing system
D. Prevent the faucet from freezing
6. A water heater has significant corrosion and active leakage around the bottom of the tank. What is the MOST appropriate recommendation?
A. Increase the thermostat setting
B. Replace the drain valve only
C. Recommend evaluation and likely replacement of the water heater
D. Install a larger expansion tank
7. What is the purpose of a dielectric fitting when certain dissimilar metals are connected in a plumbing system?
A. Increase water pressure
B. Reduce galvanic corrosion
C. Increase drainage velocity
D. Prevent freezing
8. An inspector turns on several fixtures simultaneously and notices a substantial reduction in water flow. What should the inspector suspect?
A. Excessive attic ventilation
B. A possible supply restriction or inadequate water-supply capacity
C. A blocked plumbing vent only
D. An oversized sewer line
9. Which condition is MOST concerning when inspecting a gas-fired water heater located in a garage?
A. The tank is white
B. Combustible materials are stored against or immediately adjacent to the appliance
C. Copper supply piping is present
D. The heater has a drain valve
10. What is the primary purpose of an expansion tank installed on a closed domestic hot-water system?
A. Store drinking water during an outage
B. Absorb thermal expansion as water is heated
C. Increase sewer drainage
D. Vent combustion gases
11. A sink drains slowly while other fixtures in the house drain normally. The MOST likely cause is:
A. A localized restriction in that fixture's drain
B. Failure of the main sewer line
C. Excessive municipal water pressure
D. A defective water heater
12. What is the primary concern with a plumbing supply pipe installed in an area subject to freezing temperatures without adequate protection?
A. Increased water pressure
B. Pipe rupture due to expansion of freezing water
C. Sewer gas infiltration
D. Galvanic corrosion
13. During an inspection, the inspector observes active leakage at a concealed plumbing connection that has damaged surrounding building materials. What is the BEST recommendation?
A. Paint over the staining
B. Repair the leak and evaluate the extent of moisture-related damage
C. Increase the home's water pressure
D. Install additional plumbing vents
14. What is the primary purpose of an air gap at a dishwasher drain connection when that configuration is required?
A. Increase dishwasher water pressure
B. Prevent contaminated drain water from siphoning back into the dishwasher
C. Reduce hot-water temperature
D. Increase the capacity of the garbage disposal
15. An inspector observes polybutylene (PB) water-supply piping in a house. Why should this material be specifically reported?
A. It contains lead in all installations
B. It has a history of premature failures and leakage concerns
C. It cannot carry hot water
D. It is always installed underground
16. What condition would MOST strongly suggest a possible concealed plumbing leak?
A. A slightly noisy faucet
B. Unexplained moisture staining with elevated moisture readings near plumbing
C. A white porcelain sink
D. A slow-closing toilet seat
17. When inspecting a private well system, rapid cycling of the well pump may indicate a problem with the:
A. Plumbing vent stack
B. Pressure tank or pressure-control system
C. Sewer cleanout
D. Water heater flue
18. A cross-connection in a plumbing system is a concern because it can:
A. Increase electrical consumption
B. Allow contamination of the potable water supply
C. Cause roof leakage
D. Reduce attic ventilation
19. An inspector observes water hammer when a washing machine valve closes quickly. Water hammer is caused primarily by:
A. Sudden stopping of moving water in the supply piping
B. A clogged sewer line
C. An improperly sized plumbing trap
D. Low water temperature
20. During an inspection of a septic system, sewage is observed surfacing over the drain field. What is the MOST appropriate conclusion?
A. This is normal after rainfall
B. The septic system may be failing and requires further evaluation
C. The water heater temperature is too high
D. The home's water pressure is inadequate