Gas Line Pressure Test Rules in Each Valley City

Section 406 of the International Fuel Gas Code (IFGC) sets the test, and each city can rewrite it. Phoenix's 2024 amendments change Chapter 1 and Section 403.11 (flanges) and leave Section 406 alone, so Phoenix runs the published test, the same one Chandler's permit manual prints: "no less than 1-1/2 times the proposed maximum working pressure, but no less than 3 psig."

Two more base rules apply wherever a city didn't replace them. Mechanical gauges need a scale "not greater than five times the test pressure." The hold is "not less than 1/2 hour for each 500 cubic feet (14 m3) of pipe volume or fraction thereof," dropping to 10 minutes for a system under 10 cubic feet or in a single-family dwelling. A large commercial system can need a much longer hold than a house.

Mesa, Gilbert and Queen Creek replaced that rule. Mesa's amendment reads: "The test pressure to be used shall be not less than 10 pounds per square inch (68.9 kPa) gauge pressure." Buckeye kept the 3 psig floor but wrote the 10 minute hold and gauge rule into its own amendment.

Editions differ too. Phoenix, Mesa, Chandler, Buckeye and Cave Creek (for applications from January 1, 2026) enforce the 2024 IFGC, Queen Creek the 2021, and Gilbert and unincorporated Maricopa County the 2018, each with local amendments.

Five terms decide which test applies and how it is read.

• psig. Pounds per square inch on the gauge, above the air around it.
• Working pressure. The pressure the gas runs at in the building. A home runs a fraction of a pound; some commercial systems run at 2 psi or more.
• Inches of water column. A small pressure unit used for gas. Fourteen inches is about half a psi, the line where Mesa, Gilbert and Queen Creek switch to the 60 psi test.
• Manometer or slope gauge. A liquid gauge that reads very small pressure changes, used for the inches-of-mercury option.
• Concealment. Burying the pipe or closing it in a wall. The test happens before that.

Anyone installing or altering gas piping that needs a permit, natural gas or propane, home or business. Cave Creek's checklist limits the test to "new pipe and added to an existing system," so untouched pipe is not retested when a branch is added. The county adds a case people miss: "A permit and pressure test is needed to obtain a utility clearance, even if no new work was performed."

The table shows each jurisdiction's floor; a plumber can always test higher or longer.

The gauge has to be able to show a small drop. The base code caps a mechanical gauge at five times the test pressure, which is what Phoenix and Chandler use. Gilbert wants increments of 0.10 psi or less on the 10 psi test and 1 psi or less on the 60 psi test. Buckeye wants an air gauge "calibrated in 1/10 lb. increments." Mesa sets the steps by test pressure (one-tenth of a pound up to 10 psi, 1 pound up to 100 psi) and says test gauges "shall have a pressure range not greater than twice the test pressure applied." A 0 to 100 psi gauge fails a 10 psi test in Mesa and a 3 psig test under the base code.

In Gilbert and Queen Creek, "All necessary apparatus for conducting tests shall be furnished by the permit holder."

The working pressure and the address decide the test, as these three jobs show.

A restaurant in Mesa adds a fryer line on a 2 psi system. The gas runs above 14 inches water column, so the new piping tests at 60 psi, not 3 psig. The same job in Chandler tests at 1.5 times 2 psi, which is 3 psig.

A Gilbert homeowner runs a line to a fire pit. The installer puts 10 psi on the new pipe before the trench is backfilled and holds it at least 15 minutes, and the inspector comes back after the pipe is covered.

A county property gets its gas back after a shutoff. No pipe changed, but the county still wants a permit and a pressure test before it sends the utility clearance.

Settle the test before the trench is dug, because the pipe has to stay open until it passes. The test itself is the licensed installer's job; never open or pressurize a live gas line yourself.

1. 1Find who inspects the address. City limits decide it; unincorporated addresses go to Maricopa County.
2. 2Pull the gas permit first. The gas line permit rules by city page shows each city's channel. The permit holder schedules the test inspection.
3. 3Find the working pressure. Ask the gas utility what it delivers at the meter, or read the regulator's tag on an elevated-pressure system. It decides whether the 3 psig or the 60 psi rule applies.
4. 4Make sure your installer's gauge fits the test (fine increments, a range no more than five times the test pressure, twice in Mesa) and that equipment left out of the test is "disconnected or isolated by blanks, blind flanges, or caps," as Cave Creek puts it.
5. 5Request the inspection with the pipe exposed and the test on. Chandler takes requests by text to 844-281-3520 or online. Mesa takes them online, by phone or by text, weekdays 6:30 a.m. to 5:00 p.m. In unincorporated county, requests made online by 3:30 PM are inspected the next business day, or call 602-506-3301; only a listed contact on the permit can schedule.

Most failed inspections trace back to one of these assumptions.

• "3 psi is the test everywhere." Mesa, Gilbert and Queen Creek start at 10 psi.
• "A commercial line tests like a house." Above 14 inches water column, those three towns want 60 psi.
• "Any gauge will do." The base code caps the scale at five times the test pressure, Mesa tightens that to twice, and Mesa, Gilbert and Buckeye set the increments.
• "No new pipe, no test." The county wants a pressure test for a clearance even with no new work.
• "Test it with gas." Gilbert and Queen Creek name air, CO2 or nitrogen; Cave Creek says oxygen is not allowed.

The county is direct: gas "shall not be introduced into a piping system or appliance without first being tested, inspected and approved." Cave Creek's checklist says defective piping "shall be replaced and not repaired."

This page explains the rules; each city's adopted code and inspectors govern. HQ runs, repairs and pressure tests gas lines for homes and businesses across the Valley, with free estimates and 24/7 service.