IRC G2417 Gas Pressure Test: Proving a New Gas Line Holds

Before any gas flows to a new Arizona home, the pipe has to prove it is tight. The test is simple in concept. Seal the system, pump it up with air, and watch a gauge. If the needle holds steady, there are no leaks. Section G2417 of the International Residential Code sets how that test is run and passed.

What Section G2417 requires

Section G2417 requires new gas piping to be pressure-tested and inspected before it is put into service. The installer pressurizes the sealed system to at least 1.5 times its working pressure, and never less than 3 psig, whatever the design pressure. Then the clock starts.

The test duration shall be not less than 10 minutes.

Ten minutes is the floor. Many inspectors ask for a longer hold on a larger system, and some Arizona cities set their own minimum, so the real hold time is worth confirming before the inspector shows up.

The 10-minute, 3-psi test in practice

Here is how it goes on a typical Valley job. The plumber caps every open end of the new gas piping and connects a test gauge, usually a spring gauge or a manometer. The meter and any appliances are valved off or disconnected, because the test checks the pipe, not the equipment. The system is pumped to 3 psi, or higher if the design or the city calls for it. Everyone waits at least 10 minutes and watches the needle. If it holds, the pipe passes. If it drops, there is a leak, and the code says the bad section is replaced, not patched.

What the test gas can and cannot be

The pressure is applied with air, nitrogen, carbon dioxide, or another inert gas. Oxygen is never allowed, because pure oxygen mixed with any trace of oil or gas is a real explosion risk. Leaks are found with an approved leak detector or with soap bubbles brushed on the joints, never with an open flame.

Where the test lands in your build timeline

The gas test happens at rough-in, in the same window as the framing, electrical, and plumbing inspections, before the walls close up. It is one of the checks that has to pass before the gas utility, such as Southwest Gas across most of the Valley, will set your meter and turn on service. For example, on a Cave Creek custom home the gas rough-in, the CSST bonding, and this pressure test are all confirmed together, so plan for them as one phase. A failed test that stalls that phase can hold up drywall.

Which code edition your city uses

The core test, 3 psi held for 10 minutes, reads the same across the 2018 and 2021 IRC, but the details an inspector enforces can vary by city, from a longer hold to a higher test pressure. Cave Creek, for one, inspects to the 2021 IRC, as its own fuel gas checklist shows. Check your jurisdiction's adopted edition in the building code editions by city reference, and ask the AHJ permit desk about any local test amendments. The rules for Cave Creek specifically are written up on their own page.

What the test proves, and what it does not

A passed test says the pipe is tight. It says nothing about whether the pipe was sized for the appliance load, bonded, or trapped, so it is one check among several. The piping itself is covered under fuel gas piping, and CSST bonding gets confirmed in the same visit. On the water side, plumbing tests and inspection proves the supply and waste lines the same way. Chapter 24 of the 2021 IRC has the testing text.