Plumbing Quiz
Questions: 16 · 10 minutes
1. A single-handle shower no longer gets hot enough after its handle or cartridge was serviced, but other fixtures still receive hot water. What should be checked first?
The water heater thermostat, regardless of the other fixtures
The building's main water shutoff valve
The roof vent stack for leaves
The shower's rotational limit stop or mixing-cartridge installation
2. What is the purpose of a drain cleanout?
To regulate pressure in the incoming water supply
To separate hot water from cold water
To maintain the water seal in every fixture trap
To provide access for inspecting or clearing a drain line
3. A two-handle compression faucet keeps dripping from its spout after it is turned off. Which fault is the most likely cause?
A blocked plumbing vent
An overfilled water heater
A dry P-trap beneath the sink
A worn stem washer or damaged valve seat
4. A rarely used floor drain begins releasing a sewer-like odor, but no leak or blockage is visible. What is a sensible first step?
Remove the drain grate and seal the opening with concrete
Close the building's main water valve permanently
Add water to restore a possibly evaporated trap seal
Increase the water heater temperature
5. What is a principal function of a plumbing vent system?
To admit air so drains flow properly and trap seals are protected
To carry pressurized drinking water to upper floors
To collect solid waste before it reaches the sewer
To warm drainpipes during freezing weather
6. What is the primary purpose of a P-trap beneath a sink?
To increase water pressure at the faucet
To hold a water seal that blocks sewer gases
To filter minerals out of the water supply
To provide access to the building's main shutoff valve
7. What does a pressure-reducing valve do in a water-supply system?
It lowers high incoming water pressure to a controlled downstream pressure
It pumps wastewater uphill toward the sewer
It vents sewer gases above the roof
It prevents hot water from entering cold-water piping
8. One sink faucet has weak flow from both hot and cold sides, while nearby fixtures have normal pressure. What should be checked first?
The faucet aerator for debris or mineral buildup
The building sewer connection
The water heater's temperature setting
The roof flashing around the vent pipe
9. Water is spraying from the supply connection beneath a sink. What should you do first?
Close the fixture's shutoff valve, or the main water valve if necessary
Open the faucet fully to increase flow through the connection
Remove the sink's P-trap to relieve the pressure
Pour drain cleaner into the sink to clear the supply line
10. Compared with a typical hacksaw cut, what is a key advantage of using the correct tubing cutter on suitable pipe?
It threads the end of the pipe while cutting
It eliminates the need to measure the pipe
It generally produces a cleaner, squarer cut
It automatically seals the new pipe end
11. A pipe bangs immediately after a fast-closing appliance valve shuts. What most likely causes this water hammer?
Air entering through a dry drain trap
Moving water stopping suddenly and creating a pressure surge
A drainpipe that has too much downward slope
Minerals making the water significantly heavier
12. A faucet stops flowing during freezing weather, and a frozen section of accessible pipe is suspected. Which response is appropriate?
Strike the pipe repeatedly to break the ice into pieces
Use an open flame directly on the frozen section
Close the faucet and immediately increase the building's water pressure
Open the faucet and apply gentle heat while watching for leaks and being ready to shut off the water
13. When applying PTFE thread-seal tape to the male threads of a standard tapered pipe connection, how should the tape be wrapped?
Across the pipe opening so the first turn punctures it
Back and forth lengthwise along the pipe
In the same direction the fitting turns as it is tightened
Opposite the tightening direction so it loosens during assembly
14. During heavy rain, groundwater collects in a basement sump pit. What is the sump pump designed to do?
Send drinking water from the basement to upper floors
Move collected water from the pit to an appropriate discharge point
Increase pressure in the municipal water main
Push sewage directly through fixture vent pipes
15. Why are gravity drainpipes installed with a continuous downward slope?
To raise the pressure inside fixture supply lines
To let wastewater and suspended solids move toward the outlet
To keep vent pipes filled with water
To prevent water from entering fixture traps
16. A toilet briefly refills by itself even though no one has used it. A dye test shows water slowly moving from the tank into the bowl. What is the likely problem?
The toilet's supply pressure is too low
The bowl's trapway contains no water
The flapper or flush-valve seal is leaking
The bathroom vent fan is pulling water from the tank