Home Inspector Plumbing DWV Systems Flashcards
7 cards from real Home Inspector Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Home Inspector Plumbing DWV Systems flashcards as text
What is the minimum slope required for a 3-inch horizontal drain pipe per the International Plumbing Code?
Answer: 1/8 inch per foot
A 3-inch horizontal drain requires a minimum slope of 1/8 inch per foot (approximately 1%) to ensure adequate flow.
A home inspector observes that a toilet's wax ring seal shows signs of leakage at the floor. Which DWV component is most likely failing?
Answer: The closet flange
The closet flange connects the toilet to the drain system and supports the wax ring; flange damage or improper height causes wax ring failure and leakage.
Which condition is considered a defect when inspecting a P-trap under a bathroom sink?
Answer: The trap outlet is higher than the trap inlet
A P-trap outlet higher than the inlet creates a 'S-trap' condition that allows siphoning and loss of the water seal.
What does a gurgling sound from a fixture drain typically indicate in a DWV system?
Answer: Inadequate venting causing negative pressure
Gurgling at drains signals that negative pressure in the drain line is pulling air through the fixture trap, a classic sign of inadequate venting.
Which material is NOT acceptable for use as a DWV drain pipe in residential construction under most US codes?
Answer: Galvanized steel
Galvanized steel is not approved for DWV drain applications because it corrodes internally and restricts flow; it was once used for supply lines only.
An inspector finds a washing machine standpipe that is only 12 inches tall. What is the typical deficiency?
Answer: The standpipe is too short to prevent backflow
Standpipes for washing machines must typically be 18–42 inches tall to prevent backflow and overflow onto the floor.
What is the primary purpose of a clean-out fitting in a DWV system?
Answer: To provide access for clearing blockages
Clean-out fittings provide accessible openings so drain snakes or hydro-jet equipment can be inserted to clear obstructions.