Plumbing Water Supply Systems

Question 1

What is the minimum water pressure required at a residential fixture per the IPC?

Accepted Answer

20 psi

Answer

The IPC requires a minimum static water pressure of 20 psi at every plumbing fixture to ensure adequate flow for proper operation.

Question 2

What is the maximum water pressure allowed at a residential service entrance without a pressure reducing valve (PRV)?

Accepted Answer

80 psi

Answer

Water pressure exceeding 80 psi at the service entrance requires a pressure reducing valve (PRV) to protect the plumbing system and appliances.

Question 3

What device is required to prevent backflow where a hose bib connects to a garden hose?

Accepted Answer

Vacuum breaker

Answer

A vacuum breaker (anti-siphon device) is required at hose bibbs to prevent contaminated water from being siphoned back into the potable water supply.

Question 4

What is the purpose of a pressure reducing valve (PRV) in a residential plumbing system?

Accepted Answer

To reduce high incoming water pressure to a safe level

Answer

A PRV reduces high municipal water pressure to a safe operating pressure (typically 50-60 psi) to protect fixtures, appliances, and pipes.

Question 5

Which type of water heater heats water only when it is needed, without a storage tank?

Accepted Answer

Tankless (on-demand) water heater

Answer

A tankless (on-demand) water heater heats water directly as it flows through the unit, eliminating standby heat loss associated with storage tanks.

Plumbing Practice Test