InterNACHI Plumbing Systems Inspection 2

Question 1

What is the minimum slope required for horizontal drain pipes 3 inches or smaller in diameter?

Accepted Answer

1/4 inch per foot

Answer

Horizontal drain pipes 3 inches or smaller must slope at least 1/4 inch per foot to ensure proper drainage by gravity.

Question 2

Which type of pipe is NOT approved for use as a water supply line under current plumbing codes?

Accepted Answer

Polybutylene

Answer

Polybutylene (PB) pipe was recalled and is no longer approved due to its tendency to fail and leak, especially at fittings.

Question 3

A home inspector observes that the water heater's temperature and pressure relief valve discharge pipe terminates into a bucket. This is:

Accepted Answer

A deficiency requiring correction

Answer

The TPR valve discharge pipe must terminate within 6 inches of the floor, into a drain, or to the exterior — never into a bucket or container.

Question 4

What does 'water hammer' refer to in a plumbing system?

Accepted Answer

A banging noise caused by sudden water flow stoppage

Answer

Water hammer is a pressure surge or banging noise that occurs when flowing water is abruptly stopped, often by fast-closing valves.

Question 5

An inspector finds galvanized steel supply pipes in an older home. The most likely concern is:

Accepted Answer

Internal corrosion reducing water flow and pressure

Answer

Galvanized steel pipes corrode from the inside over time, restricting flow, reducing pressure, and eventually leaking.

(InterNACHI) International Association of Certified Home Inspectors Practice Test