What do I do if my water heater pilot light is out and I smell gas?

A pilot that goes out on its own is usually not dangerous, because the gas control is built to close. On many newer tanks, the pilot flame heats a small sensor called a thermopile; older designs use a thermocouple that does the same job. State Water Heaters' service handbook explains that when the thermopile is heated by the pilot, it makes a small voltage, and "This voltage opens the power head in the control, allowing gas to flow." No flame means no voltage, so the valve should stay shut.

That is why a pilot outage with no gas smell is a relight job, and a pilot outage with a gas smell is not. The two call for opposite first steps:

A.O. Smith's status light chart describes the solid red state as "Pilot light was recently extinguished and the thermopile is cooling down," and says to turn the knob to OFF and wait 10 minutes before relighting.

Get out first, then call. Southwest Gas's safety page lists the steps, and they apply whether or not the pilot is lit:

1. 1Leave the area immediately. Tell others to leave, and leave doors open.
2. 2Don't create a spark. Southwest Gas says don't turn "on or off any electric switches, thermostats, or appliance controls," and don't smoke or use matches or lighters.
3. 3Leave the car alone. Don't start or stop an engine or use an automatic garage door. That matters in Phoenix, where so many water heaters sit in the garage.
4. 4Call from a safe place. Call 911 and Southwest Gas at 877-860-6020, day or night.

The lighting label on an A.O. Smith tank says the same thing in the manufacturer's words. Under "What to do if you smell gas," it says: "Do not try to light any appliance," "Do not touch any electric switch; do not use any phone in your building," and "Immediately call your gas supplier from a neighbor's phone."

Southwest Gas also sets a low bar for what counts. It says to act on a rotten egg smell "even if it's faint or momentary." Don't stand in the garage sniffing to decide how bad it is. Natural gas has no odor of its own, and Southwest Gas adds an odorant called mercaptan so you can notice a leak. The smell is the warning. Treat it as one.

You would smell gas because gas is escaping somewhere, and a technician needs to find where. From the house you can't tell, but these are the usual places a leak turns up around a water heater:

• Gas left from lighting attempts. A try that doesn't catch can leave unburned gas in the burner area. The A.O. Smith label tells you to turn the knob to OFF and "Wait ten (10) minutes to clear out any gas. If you then smell gas, STOP!" A smell that is still there after the wait is not leftover gas from the attempt.
• The appliance connector. The flexible line from the shutoff valve to the water heater can leak at its fittings. Southwest Gas warns that "Some older brass flexible connectors can separate from the tubing and cause a gas leak, explosion, or fire."
• The shutoff valve or the piping near the tank, at a threaded joint or a valve stem.
• The gas control itself, if it fails to close fully.
• A different appliance. The furnace, dryer, or range can be the source even when the water heater is what you were looking at.

That list is why a relight is the wrong move. Lighting the pilot means making a flame and a spark in the one room where gas is most likely to be.

### Is a faint smell after a relight attempt normal?

Treat it as a leak. The manufacturer's instructions build in a wait so any gas from a lighting attempt can clear, and they say to stop if you still smell gas after it. Southwest Gas says a smell counts even when it is faint. Put those together and there is no "normal" smell to wait out. Get out and call.

The label also says to smell next to the floor before lighting, "because some gas is heavier than air and will settle on the floor." That line covers propane, which settles, as our page on natural gas vs propane at home explains. Southwest Gas notes that natural gas is "lighter than air," so it rises. Check low and high before you ever strike a spark.

Southwest Gas makes the area safe, finds the source, and tells you what has to be fixed. Its Arizona tariff says that when an unsafe or hazardous condition is found on the customer's premises, service may be disconnected without notice, and the utility "will attempt to notify the customer or occupant immediately of the reasons for the discontinuance and the corrective action to be taken by the customer before service can be restored."

What comes next depends on where the leak is:

• Leak at the water heater or its connector. The technician may shut off gas to that appliance only. A licensed plumber replaces the connector, valve, or gas control, and checks the joints for leaks.
• Leak in the house piping. Southwest Gas may lock the meter. In Phoenix, a meter locked for a leak on the customer side needs a city permit, a city inspection, and a city gas clearance before it is unlocked, according to the gas clearance table the city published with Southwest Gas and the Arizona Corporation Commission.
• No leak found. Once the area is cleared, you can relight the pilot using the label.

Only Southwest Gas turns the gas back on at a locked meter. Its tariff says only its "duly authorized employees or agents" can turn on the utility's supply of gas.

It's safe to relight once there is no gas smell, and after Southwest Gas or a technician has cleared the area if there was one. Then follow the lighting label on your own tank, step by step. A.O. Smith's version runs like this:

1. 1Turn the gas control knob to OFF.
2. 2Wait 10 minutes to clear out any gas. Smell all around the tank, including near the floor. If you smell gas, stop.
3. 3Turn the knob to PILOT, press and hold it, and click the igniter about once a second for up to 90 seconds, until the status light blinks.
4. 4Release the knob and set the temperature.

A.O. Smith says that if the status light doesn't start blinking within 90 seconds, you can repeat the steps up to three times, "waiting 10 minutes between lighting attempts," and then turn the knob to OFF and call a qualified service technician. Its gas valve has "built-in circuitry that requires waiting 10 minutes between lighting attempts." Other brands set their own wait. Use the time on your label, not a number from memory.

### Why does the pilot keep going out in a Phoenix garage?

Heat is part of it. State's handbook lists "Elevated air temperature" first among the causes of pilot outage, and explains that the flame arrestors and sealed chambers on modern tanks "also make them more sensitive to high ambient temperatures." It also lists insufficient makeup air, a blocked air screen or flame arrestor, and improper venting. A pilot that keeps dying is a service call, not a relight habit. Our page on why a water heater pilot light won't stay lit walks through the parts that cause it, and venting problems also tie into whether a water heater can cause carbon monoxide.

HQ Plumbing & Air repairs gas water heaters and gas lines across the Phoenix area, with 24/7 emergency service once Southwest Gas has made things safe. For the leak steps in more detail, see what to do when the house smells like gas. If the heater is acting up for no clear reason, you can also check it for a safety recall.

Smell gas, skip the relight. Out first, then call.