Journeyman Plumber ExamWater Supply SystemsMedium
A plumber is performing a rough-in inspection for a new water distribution system. The system includes copper, PEX, and CPVC piping. Before the final connections are made, the system must be pressure tested. What is the generally accepted minimum test pressure and duration for a water distribution system, according to most plumbing codes?
- A125 psi or 50 psi above working pressure, for 15 minutes (whichever is greater)
- B50 psi for 15 minutes
- C100 psi for 15 minutes
- D200 psi for 30 minutes
Show answer & explanationAnswer & explanation
Correct answer: A. 125 psi or 50 psi above working pressure, for 15 minutes (whichever is greater)
Most plumbing codes (e.g., UPC, IPC) require a minimum test pressure of 125 psi or 50 psi above the working pressure, whichever is greater, and for a duration of at least 15 minutes. This ensures the system can withstand normal operating conditions and potential surges without leakage.
Why the other options are wrong
- B. 50 psi for 15 minutes is typically too low for a robust pressure test.
- C. While 100 psi is closer, it might not meet the '50 psi above working pressure' clause if actual working pressure is high, and 15 minutes is the minimum duration.
- D. 200 psi for 30 minutes is a very high test pressure and duration, often exceeding typical code requirements and potentially overstressing the system unnecessarily.
Water System Pressure Test
A procedure to verify the integrity and leak-free performance of a newly installed or repaired water distribution system by subjecting it to a specified pressure for a set duration.
- Required before concealing piping.
- Ensures system can withstand working pressure plus surge.
- Pressure gauge must remain steady for the duration.
Memory trick: Pressure test: 125 or 50 over, for 15 mins, no leaks to discover.