InterNACHI Plumbing Systems Inspection 5 — Questions and Answers
Question 1: An inspector observes a double-tapped (two hoses connected to one fitting) washing machine supply hose connection at the valve. This is:
- Acceptable if both hoses are braided stainless
- Not a plumbing concern — only an electrical term
- A deficiency; each supply connection requires its own dedicated valve (Correct answer)
- Permitted if total flow does not exceed valve rating
Correct answer: A deficiency; each supply connection requires its own dedicated valve
Each washing machine supply hose should connect to its own dedicated shutoff valve; sharing a single valve connection is improper and creates reliability issues.
Question 2: What is the primary concern with a sump pump that discharges into the sanitary sewer system?
- The sump pump motor may overheat
- It introduces groundwater into the sewage system, which is prohibited in most jurisdictions (Correct answer)
- The discharge pipe diameter is usually too small
- It causes the sump pit to fill too quickly
Correct answer: It introduces groundwater into the sewage system, which is prohibited in most jurisdictions
Discharging groundwater (clear water) into the sanitary sewer is prohibited in most areas because it overloads the sewage treatment system.
Question 3: When inspecting a bathroom, the inspector finds no ventilation fan and no window. This is a concern because:
- It violates the NEC electrical code
- Moisture buildup can lead to mold growth and structural damage (Correct answer)
- All bathrooms require at least two ventilation sources
- The toilet will not flush properly without ventilation
Correct answer: Moisture buildup can lead to mold growth and structural damage
Bathrooms without mechanical ventilation or an operable window are prone to moisture accumulation, which promotes mold, mildew, and deterioration of finishes and structure.
Question 4: What condition is indicated when a toilet continues to run after the tank has fully refilled?
- The supply stop valve is partially closed
- A faulty flapper or flush valve is allowing water to leak into the bowl (Correct answer)
- The fill valve float is set too low
- The toilet requires a higher water pressure to operate
Correct answer: A faulty flapper or flush valve is allowing water to leak into the bowl
A continuously running toilet is most commonly caused by a worn or misaligned flapper that fails to seal the flush valve, allowing tank water to slowly drain into the bowl.
Question 5: Which of the following materials is commonly used for drain, waste, and vent (DWV) piping in modern residential construction?
- Galvanized steel
- Copper type M
- ABS or PVC plastic (Correct answer)
- Cast iron only
Correct answer: ABS or PVC plastic
ABS (acrylonitrile butadiene styrene) and PVC (polyvinyl chloride) are the most common materials used for DWV systems in modern residential construction.
Question 6: An inspector notices that the cleanout plug on a main drain cleanout is missing. The significance of this finding is:
- No concern — cleanouts are optional access points
- Sewer gases can enter the home and vermin can access the drain system (Correct answer)
- The drain system will not function without the plug
- Only significant if the home has a septic system
Correct answer: Sewer gases can enter the home and vermin can access the drain system
A missing cleanout plug allows sewer gases to escape into the structure and provides an entry point for insects and rodents into the drain system.
Question 7: What does it mean when a home inspector reports 'evidence of prior repair' at a plumbing pipe?
- The pipe has been recently replaced and is in excellent condition
- There are visible signs of past leaks or patching that may indicate ongoing problems (Correct answer)
- The repair was permitted and should be trusted
- The pipe material was upgraded from an older type
Correct answer: There are visible signs of past leaks or patching that may indicate ongoing problems
Evidence of prior repair (tape, epoxy, clamps, or staining around a patch) suggests the area has experienced past failure and warrants closer evaluation for recurring issues.
InterNACHI Plumbing Systems Inspection 5
An inspector observes a double-tapped (two hoses connected to one fitting) washing machine supply hose connection at the valve.
This is: