No code sets a calendar for inspecting existing home gas lines in Phoenix. The guidance is to have gas appliances inspected every year by a licensed plumber and to have buried gas lines inspected periodically for leaks and corrosion. Also inspect after the gas has been off, before buying a house, and after any digging near a line.
What does the code require for gas line inspections?
The code requires an inspection when gas piping is new or altered, and that is where it stops. Phoenix enforces the 2024 International Fuel Gas Code. Section 406.1 says that "Prior to acceptance and initial operation, all piping installations shall be visually inspected and pressure tested." Section 404.20 adds that piping must be tested "Before any system of piping is put in service or concealed."
The city's gas clearance table sets out when that inspection happens on an existing building. A city permit, inspection, and gas clearance are required for:
- New gas piping, like a line to a new range, grill, or pool heater.
- Changes to existing piping, other than installing an appliance connector.
- A meter locked by Southwest Gas for a leak on the customer side.
- Repairs where the gas was shut off at the building.
- An appliance upgrade that adds BTU load and needs pipe capacity calculations.
Outside of those events, nothing in the code sends an inspector back to piping that is already in service. The schedule is up to the owner.
How often should gas appliances be inspected?
Gas appliances should be inspected once a year by a licensed plumber. Southwest Gas's safety guidance says: "Make sure that licensed plumbers install and repair natural gas equipment and appliances, as well as perform annual inspections and maintenance on your gas appliances."
A yearly visit is also a natural time to look at the gas piping the plumber can see: the shutoff valves, the appliance connectors, and the exposed runs in the garage, laundry, and water heater closet. Two things to ask about during that visit:
- Old brass connectors. Southwest Gas warns that "Some older brass flexible connectors can separate from the tubing and cause a gas leak, explosion, or fire," and says uncoated brass connectors should be replaced with stainless steel or plastic-coated ones.
- Flame color. Southwest Gas says a properly working gas appliance "should have a clear, steady blue flame," and that "Yellow flames may indicate improper combustion and can be a safety concern." Decorative fireplaces, fire pits, and tiki torches are the exception, and Southwest Gas notes that dust or lint can briefly turn a flame orange. A yellow flame on a water heater or furnace is a reason to call Southwest Gas at 877-860-6020, which its FAQ says to do right away.
Keep three feet of clear space around the water heater and furnace while you are at it. Southwest Gas lists that as a basic safety habit.
How often should buried gas lines be inspected?
Periodically, and the owner decides the interval. Federal pipeline rules require gas utilities that do not maintain customer buried piping to send a written notice, and that notice has to say buried gas piping should be "Periodically inspected for leaks," "Periodically inspected for corrosion if the piping is metallic," and "Repaired if any unsafe condition is discovered." Southwest Gas's brochure gives the same advice: "Periodically inspect your lines for leaks and/or corrosion."
Neither source puts a number on "periodically." A sensible way to set one:
| Buried line | Suggested approach |
|---|---|
| Plastic line with tracer wire, recently installed and tested | Check when other gas work is done, or when something changes |
| Older metal line, or one of unknown age | Have it located and tested sooner rather than later, then on a regular cycle you set with your plumber |
| Line under a yard that gets dug, trenched, or landscaped | Check after the digging |
| Long line from a meter at the property line | Treat it as the highest priority, since it is the most pipe you own |
Metal pipe underground is the reason for the corrosion warning. The fuel gas code says "Zinc coating shall not be deemed adequate protection for underground gas piping," so galvanized steel buried without a real coating is exactly the kind of line the notice is written about.
When should you get a gas line inspected right away?
Some events call for a check now, whatever the calendar says. These are the ones worth acting on:
- You smell gas, hear hissing, or see bubbling water or dead grass over a buried line. Get out and call 911 and Southwest Gas at 877-860-6020 first. Inspection comes after.
- The gas has been off. When service is turned on, Southwest Gas runs a leak check on the customer's piping, and its tariff says service is denied if uncontrolled leakage exists. Testing beforehand avoids a failed turn-on.
- You are buying or selling a house. A standard home inspection does not pressure test gas lines or check buried ones.
- Someone dug near a buried line. Southwest Gas warns that customer buried piping can't be located by calling 811, so a line can be hit by accident.
- You are adding a gas appliance. A bigger water heater, a tankless unit, or a pool heater may need pipe sizing, which is permit work in Phoenix.
- A landlord, lender, insurer, or inspector asks for proof. That calls for a written test result or certificate.
Our guide to whether home inspectors check gas lines covers the buying case in detail.
### What does a gas line inspection include?
A full gas line inspection pairs a visual walk-through with a pressure test. The plumber checks the piping, valves, and connectors from the meter to each appliance, then caps the system and pumps it up with air or nitrogen. Under the fuel gas code Phoenix uses, the test pressure is at least 1.5 times the working pressure and never below 3 psig, held for at least 10 minutes in a single-family home. Any drop on the gauge counts as a leak unless another cause is clear. If one turns up, the leak is found with a gas detector or leak detection fluid, repaired, and tested again.
Does Southwest Gas inspect my gas lines?
Southwest Gas surveys its own lines, not yours. Its FAQ says its employees and contractors generally come to a home only when service is requested, "except in the case of performing routine leak surveys." Those surveys cover the utility's system. The federal notice rule exists because the utility does not maintain the customer's buried piping, and Southwest Gas's tariff says it has "no duty to inspect, maintain, or repair the customer's premises" beyond what its rules provide.
The one check you do get is at turn-on, when the utility runs a leak check on your piping. That is a snapshot, not a maintenance plan.
HQ Plumbing & Air inspects and pressure tests natural gas systems for homes and businesses across the Phoenix area, with a written certification letter when the system passes. See our gas leak inspection service, with free estimates and the price up front.
Appliances every year. Buried lines on a schedule you set. Everything else when something changes.