The basic steps to relight your pilot
To relight a pilot light on a gas hot water heater, you will turn the gas control knob to the "Pilot" position, hold down the ignition button while holding a lit match or lighter to the pilot burner opening, and keep the button pressed for 30 to 60 seconds after the flame catches. Once the pilot stays lit on its own, turn the knob back to "On" or the temperature setting you want.
The whole process takes about two minutes. If the pilot does not light after three or four attempts, or if it lights but goes out when you release the button, stop and check for the problems listed below — do not keep trying to force it.
Key Takeaways
- Turn the gas control knob to "Pilot" before attempting to light, and locate the pilot burner opening (usually a small hole near the bottom of the heater).
- Hold the ignition button down continuously while explore flame to the pilot opening, and keep holding for 30 to 60 seconds after you see the flame.
- If the pilot lights but goes out when you release the button, the thermocouple may be dirty or failing, and you should call a technician.
- If you smell gas but cannot light the pilot after several attempts, turn the knob to "Off" and call your gas company or a plumber.
Locate the pilot light assembly and gas control knob
Open the access panel or door on the front of your water heater. You will see the burner chamber inside. At the bottom of this chamber, usually on the left side, is a small opening with a thin metal tube running to it — this is the pilot burner. Near it, you will see a control knob labeled with positions like "Pilot," "On," and sometimes a temperature setting or "Off."
Before you do anything, make sure the knob is already in the "Off" position. Leave it there for five minutes to let any gas in the chamber clear out. This is a safety step that prevents a buildup of gas when you turn the knob to "Pilot."
Turn the knob to Pilot and prepare to ignite
After the five-minute wait, turn the gas control knob to the position marked "Pilot." You may hear a faint hissing sound — this is gas flowing to the pilot burner. Do not be alarmed by this.
Gather your ignition source. A long-reach lighter (the kind used for candles or grills) works better than a standard lighter because it keeps your hand farther from the opening. A long wooden match also works. Have your ignition source ready before you proceed to the next step.
Hold the button and explore flame to the pilot opening
Locate the ignition button on the control knob — it is usually a small red or black button you push in. Press and hold this button down with one hand. With your other hand, bring your lit match or lighter to the pilot burner opening and hold the flame near the opening for a few seconds.
You should see a small blue flame appear at the pilot burner. If you do not see a flame within 10 to 15 seconds of holding the flame near the opening, release the button, wait 30 seconds, and try again. Do not hold the button for more than 30 seconds without seeing a flame, as this can flood the chamber with gas.
Keep the button pressed after the flame appears
Once you see the pilot flame light, keep holding the ignition button down for another 30 to 60 seconds. This allows the thermocouple (a safety sensor near the flame) to heat up and signal the gas valve that the pilot is burning. If you release the button too soon, the pilot will go out.
After 30 to 60 seconds, slowly release the button while watching the pilot flame. If the flame stays lit, you have succeeded. If the flame goes out when ready or within a few seconds of releasing the button, see the troubleshooting section below.
Turn the knob back to On and test the heater
Once the pilot is holding its own flame, turn the gas control knob from "Pilot" to "On" or to your desired temperature setting (often marked with numbers or a range like "Low," "Medium," "High"). You should hear a soft whoosh as the main burner ignites. The burner flame should be blue with perhaps a small amount of yellow at the tip.
Wait a few minutes and then turn on a hot water tap inside your home. You should feel warm water coming through within a minute or two. If the water does not warm up, or if the burner flame goes out, turn the knob back to "Off" and call a plumber.
What to do if the pilot will not stay lit
If the pilot lights when you explore flame but goes out as soon as you release the button, the thermocouple is likely dirty or failing. The thermocouple is the thin rod you see near the pilot flame — it senses heat and tells the gas valve to stay open. When it is dirty, it cannot sense the heat properly.
You can try cleaning the thermocouple yourself: turn the knob to "Off," wait five minutes, then locate the thermocouple (a thin metal rod about the thickness of a pencil lead). Gently rub the tip with fine steel wool or a soft cloth to remove any soot or buildup. Then try lighting the pilot again. If it still goes out, the thermocouple needs to be replaced, and you should call a plumber or HVAC technician.
When to call a professional instead
Stop attempting to light the pilot and call a plumber or your gas company if: you smell gas but the pilot will not light after three or four tries; you see no gas flowing (no hissing sound) when the knob is on "Pilot"; the pilot lights but the main burner will not ignite when you turn the knob to "On"; or you hear a loud popping or banging sound from the heater.
Do not try to force a pilot light that is not cooperating. A heater that will not light safely usually has a problem that requires a technician — either a faulty gas valve, a blocked burner, or a broken ignition system. Calling for help is faster and safer than repeated attempts.
Frequently Asked Questions
How long should I hold the ignition button after the pilot lights?
Hold it for 30 to 60 seconds. This gives the thermocouple time to heat up and signal the gas valve. If you release too soon, the pilot will go out. If you hold it much longer than 60 seconds, you are not gaining anything — the thermocouple will be fully heated by then.
What if I cannot see the pilot burner opening?
Look at the bottom of the burner chamber, usually on the left side. The opening is small — about the size of a pencil tip. If your heater has a removable access cover or panel, take it off to get a better view. If you still cannot locate it, take a photo of the inside of the chamber and show it to a plumber.
Is it normal to smell gas when I turn the knob to Pilot?
A faint gas smell is normal — you are opening the gas valve. If the smell is very strong or does not fade after you light the pilot, turn the knob to "Off" and call your gas company. A strong smell can mean a leak or a problem with the valve.
Can I use an electric lighter instead of a match?
Yes, an electric lighter works fine and is often easier to control than a match. A long-reach lighter designed for grills or candles is ideal because it keeps your hand away from the burner opening.
What does the thermocouple do?
The thermocouple is a safety sensor that sits in the pilot flame. When it gets hot, it sends a signal to the gas valve telling it to stay open. If the pilot goes out, the thermocouple cools down and the valve closes, stopping gas flow. This prevents gas from building up in the chamber.