Home Inspector Plumbing & Fuel Systems Practice Questions
Plumbing & Fuel Systems makes up 3 of every 50 questions on a Tigertest Home Inspector practice test. Here are 10 of the 12 questions on it, each with the answer and the reason.
Updated by the Tigertest team. Based on the EBPHI content outline for the National Home Inspector Examination. Original questions; 50 per test, weighted like the real 200-question exam. Not affiliated with EBPHI.
1. The discharge pipe from a water heater temperature and pressure relief valve should:
- A.Step down to a smaller pipe size
- B.End within 6 inches of the floor
- C.Have threads at its open end
- D.Pass through a shutoff valve
Answer: B. The TPR discharge runs full size, by gravity, with no valve and no threaded end, and ends no more than 6 inches above the floor or a drain.
2. A water heater on a system with a check valve or pressure reducing valve on the supply usually needs:
- A.A gas sediment trap
- B.A vacuum breaker cap
- C.A second relief valve
- D.A thermal expansion tank
Answer: D. In a closed system, heated water cannot push back into the main. An expansion tank absorbs the extra volume so the TPR valve does not open.
3. A gauge on an outdoor hose bibb reads 95 psi with no water running. The inspector should recommend:
- A.A pressure reducing valve
- B.A backflow preventer
- C.A thermal expansion tank
- D.A larger water meter
Answer: A. The IRC calls for a pressure reducing valve when static pressure exceeds 80 psi, since high pressure strains fixtures and supply lines. An expansion tank only absorbs heated water.
4. Copper pipe joined directly to galvanized steel pipe tends to cause:
- A.A cross-connection
- B.Thermal expansion
- C.Galvanic corrosion
- D.Water hammer
Answer: C. Dissimilar metals in contact through water form a galvanic cell, and the steel corrodes. A dielectric union separates them.
5. Gray flexible water supply pipe installed from about 1978 to 1995, often stamped PB2110, is:
- A.CPVC
- B.Polyethylene
- C.Polybutylene
- D.PEX
Answer: C. Polybutylene was widely used then and is known for failing at fittings and from chlorine in the water. Inspectors report it for evaluation.
6. An S-trap under a sink is a defect because it can:
- A.Siphon its water seal
- B.Restrict drain flow
- C.Freeze more easily
- D.Collect too much hair
Answer: A. The S shape lets the falling water pull the trap dry, which lets sewer gas into the room. A P-trap with a vent keeps the seal.
7. An air admittance valve on a drain must be:
- A.The only vent for the house
- B.Hidden inside a wall cavity
- C.Set below the trap arm
- D.Accessible and above the drain
Answer: D. AAVs open to let air in when the drain flows. They must stay reachable for replacement and sit at least 4 inches above the drain they vent, and at least one vent must still run to the outdoors.
8. Horizontal drain pipe 2 1/2 inches or smaller in diameter should slope at least:
- A.1 inch per foot
- B.1/4 inch per foot
- C.1/8 inch per foot
- D.1/2 inch per foot
Answer: B. Small drains need 1/4 inch per foot to carry solids. Pipe 3 to 6 inches may slope 1/8 inch per foot.
9. Shower and tub-shower control valves must limit the water temperature at the outlet to no more than:
- A.140 degrees F
- B.120 degrees F
- C.110 degrees F
- D.130 degrees F
Answer: B. Pressure balance or thermostatic valves with a limit stop set at 120 degrees F reduce the risk of scalding.
10. An outdoor hose bibb with no vacuum breaker is a concern because it can:
- A.Cut the water pressure
- B.Cause water hammer
- C.Freeze the valve stem
- D.Contaminate the supply
Answer: D. A hose left in a bucket or pool can be siphoned back into the drinking water during a pressure drop. A vacuum breaker stops back-siphonage.
Practice all 12 plumbing & fuel systems questions, and the rest of the 200-question bank, in the free Home Inspector training sets. Questions you miss come back until you have mastered them.
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