Lighting the Pilot Light: The Basic Steps

To light a hot water heater pilot light, you turn the gas control knob to "Pilot," 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 appears. Once the pilot stays lit on its own, turn the knob to "On" and listen for the main burner to ignite within a minute or two. If the pilot won't stay lit after you release the button, the thermocouple—a safety device that senses heat—may need cleaning or replacement.

The whole process takes about five minutes if everything works. If you smell gas at any point, stop when ready, leave the area, and call your gas company's emergency line. Do not use electrical devices, light switches, or create any spark.

Key Takeaways

  • Turn the gas control knob to "Pilot," press the ignition button, and hold a flame to the pilot opening for 30 to 60 seconds while the button is held down.
  • Once the pilot flame appears and stays lit after you release the button, turn the knob to "On" to let the main burner ignite.
  • If the pilot light goes out when ready after you release the button, the thermocouple may be dirty or faulty and needs inspection.
  • If you smell gas or cannot get the pilot to light after three attempts, stop and contact your gas company or a licensed technician.

Locate the Pilot Light Assembly and Control Knob

Open the access panel on the front or bottom of your water heater—it is usually held by one or two screws or clips. Inside, you will see a small metal tube (the pilot burner) and a control knob labeled with settings like "Off," "Pilot," and "On." The knob may also have a temperature dial. Some heaters have the knob on the outside of the tank; others require you to open a panel to reach it.

Before you touch anything, make sure the heater has been off for at least five minutes. This lets any residual gas clear from the chamber. Look for the ignition button near the control knob—it is usually a small red or black button you press down and hold. If your heater is very old, it may not have an ignition button and will require a match or lighter only.

Turn the Knob to Pilot and Press the Ignition Button

Rotate the control knob clockwise until it points to "Pilot." You will hear or feel a slight click. Now press and hold the ignition button down firmly. You should hear a clicking sound as the ignition sparks. Keep the button pressed the entire time you are lighting the pilot.

While holding the button down, bring a lit match or lighter to the opening of the pilot burner tube. The flame should catch within a few seconds. If it does not light after 10 seconds, release the button, wait 30 seconds for gas to clear, and try again. Do not attempt more than three times in a row—if it will not light, stop and let the heater sit for several minutes before trying again.

Keep the Button Pressed While the Pilot Flame Appears

Once you see the pilot flame, continue holding the ignition button down for another 30 to 60 seconds. This time allows the thermocouple to heat up and signal the gas valve that the pilot is burning safely. If you release the button too soon, the pilot will go out because the thermocouple has not warmed enough yet.

Watch the flame while you hold the button. It should be blue with a small yellow tip, about the size of a pea. If the flame is very small, orange, or flickering wildly, the burner opening may be clogged with dust or debris. In that case, release the button, let the heater cool, and gently clean the opening with a thin wire or compressed air before trying again.

Release the Button and Turn the Knob to On

After 30 to 60 seconds, slowly release the ignition button while watching the pilot flame. If the flame stays lit, you have succeeded. Now rotate the control knob to "On." Within 30 to 60 seconds, you should hear a soft whoosh as the main burner ignites. The main burner flame will be much larger than the pilot and should be blue.

If the pilot goes out the moment you release the button, the thermocouple is not sensing the heat properly. Wait five minutes and try again, this time holding the button for the full 60 seconds. If it goes out again, the thermocouple likely needs cleaning or replacement—see the troubleshooting section below.

Troubleshooting When the Pilot Won't Stay Lit

The most common reason a pilot light will not stay lit is a dirty thermocouple. The thermocouple is a thin metal rod that sits in the pilot flame and generates a small electrical signal when heated. If dust or corrosion blocks this signal, the gas valve closes automatically as a safety measure. To clean it, turn the knob to "Off," let the heater cool for 10 minutes, and locate the thermocouple—it is the thin rod closest to the pilot burner opening.

Gently rub the tip of the thermocouple with fine steel wool or a soft cloth to remove any buildup. Do not bend it or explore heavy pressure. Reassemble the panel and try lighting the pilot again. If the pilot still goes out, the thermocouple may be faulty and will need replacement by a licensed technician. A new thermocouple costs between $15 and $40 in parts, but installation requires someone trained to work safely with gas lines.

If the pilot lights but the main burner does not ignite after you turn the knob to "On," the issue is usually a clogged main burner opening or a problem with the gas valve itself. Do not attempt to repair the gas valve—call a technician. If you smell gas at any time, turn the knob to "Off," leave the house, and call your gas company's emergency number.

When to Call a Professional

Stop trying to light the pilot and call a licensed technician if: the pilot will not light after three separate attempts, the pilot lights but goes out when ready even after you hold the button for a full minute, you smell gas coming from the heater, or the main burner will not ignite after the pilot is lit. Attempting to force a repair on a gas appliance can be dangerous and may void your warranty.

Most water heater companies recommend having the heater inspected once a year by a professional. If your heater is more than 10 to 15 years old and the pilot keeps going out, replacement may be more cost-effective than repeated repairs. A technician can assess whether the thermocouple, gas valve, or the heater itself is the problem.

Frequently Asked Questions

How long should I hold the ignition button down?

Hold it for 30 to 60 seconds after the pilot flame appears. This gives the thermocouple time to heat up and signal the gas valve to stay open. If you release too soon, the pilot will go out because the thermocouple has not warmed enough.

What does the pilot flame look like when it is working correctly?

A healthy pilot flame is blue with a small yellow tip, about the size of a pea. If the flame is mostly orange, very small, or flickering erratically, the burner opening is likely clogged with dust and needs gentle cleaning with a thin wire or compressed air.

Can I use an electric lighter instead of a match?

Yes. An electric lighter works just as well as a match and is often easier to control. Avoid lighters with long flames that are hard to aim at the small pilot opening. A long-reach lighter designed for candles works well.

What should I do if I smell gas while lighting the pilot?

Stop when ready, turn the knob to "Off," leave the house, and call your gas company's emergency line from outside. Do not use electrical devices, light switches, or create any spark. A gas leak is a serious safety hazard.

How often do I need to relight the pilot?

Under normal conditions, the pilot should stay lit continuously. If it goes out regularly, the thermocouple is likely dirty or faulty. A thermocouple that needs cleaning or replacement is the most common reason for repeated pilot outages.