Pressure test

No gas reaches a new Arizona home until the pipe proves it is tight. The pressure test is how it proves that, and the method is old and simple. Cap every open end, disconnect the piping from the meter or the propane tank, close the appliance valves, and pump the system full of air. Then stand there and watch the gauge. A needle that holds means no leak.

Section G2417 of the 2021 International Residential Code sets the floor. The test pressure runs at least 1.5 times the maximum working pressure and never below 3 psig, whatever the design calls for. The hold is at least 10 minutes. The pressure comes from air, nitrogen, carbon dioxide, or another inert gas, never oxygen, because oxygen meeting a trace of pipe oil is an explosion risk. Leaks get found with soap bubbles or an approved detector, never a flame.

Arizona jurisdictions routinely ask for more than the code floor, so the IRC number alone will not get you signed off. For example, Pinal County requires 10 psi, more than three times the minimum, on a gauge no larger than 30 psi, and the pressure has to hold while the inspector watches for at least 10 minutes. The bulletin also puts the burden on you: the system must already be under test pressure when he arrives, not pumped up after.

The test lands at rough-in, in the same visit as framing, electrical, and plumbing, before drywall closes the walls. That is also the visit where the CSST bonding gets confirmed, so treat gas rough-in as one phase. Passing it is what lets Southwest Gas set your meter and turn on service. Fail it and the code answer is to replace the defective section, not patch it, which is why a bad gas test can push drywall by a week.