Why your gas water heater’s pilot light won’t light and how to fix it: A DIY guide

Is your gas water heater pilot light not lighting? You’re not alone. Many homeowners face this common issue at least once while they own a gas unit. Luckily, you can get your pilot light burning again in no time — without an expensive service call.

If you need any replacement parts for your appliances, you can enter your model number at AppliancePartsPros.com to order them. Most orders arrive in just two business days, and we have thousands of free guides to show you how to install your new parts.

Note: While we strive to offer helpful advice for DIY appliance repairs, the information in this article may differ from your specific appliance model. Variations in models and configurations can lead to differences in troubleshooting steps, error codes and part replacements. For the most accurate guidance, we strongly recommend consulting the technical sheet for your specific appliance model before beginning any testing or repairs.

5 common reasons why a water heater pilot light won’t light up

A properly functioning pilot light is needed to ignite the burner that heats your water. Without it, your gas water heater is rendered useless.

Here are the top causes behind a pilot light that won’t ignite and how you can address them.

1. Faulty thermocouple 

The thermocouple is a safety feature that keeps the gas flowing only when the pilot light is lit. If it’s dirty or damaged, the thermocouple may not be able to detect the flame, which can cause the water heater’s pilot light to go out repeatedly.

How to fix it:

• Clean the thermocouple with a dry cloth to remove dirt or grime.
• Check for any bends or misalignments that might prevent it from properly detecting the pilot light.
• If the thermocouple is broken, replace it with a new one.

2. Clogged pilot orifice

A blocked pilot orifice can prevent gas from reaching the pilot light. Dust and debris can build up, which limits gas flow and prevents the light from igniting.

How to fix it:

1. Shut off the gas supply to your water heater.
2. Remove the pilot orifice and carefully clean it with compressed air or a fine wire.
3. Reattach the orifice and attempt to relight the pilot light.

3. Bad gas control valve

The gas control valve regulates the flow of gas to your water heater’s burner and pilot light. When this valve malfunctions, it can cut off the gas supply completely.

How to fix it:

Listen for gas flow when you try to ignite the pilot light. If there’s no gas, the control valve may need to be replaced.

4. Air in the gas line

If there’s air trapped in the gas line, it can prevent the pilot light from igniting due to the inability for the gas to flow freely.

How to fix it:

Turn off the water heater and allow the air to dissipate by attempting to light the pilot light several times.

If the issue persists, consult a licensed professional to safely purge the gas line of air.

5. Drafty environment

Sometimes the pilot light goes out because of an overly drafty environment. If your water heater is in an area with poor insulation or too much airflow, small gusts of wind can extinguish the pilot light.

How to fix it:

• Check for any open windows or doors near your water heater that could cause drafts.
• Fill any gaps that could be letting outside air into the space.
• Install a draft shield or move the water heater to a more protected location if necessary.

How to reset a water heater pilot light

1. Set the gas control valve to the “OFF” position and wait a few minutes to allow any gas buildup to dissipate.
2. Turn the control valve to the “PILOT” position.
3. Press down on the gas control knob and use a long lighter to ignite the pilot light. Hold the knob down for 30-60 seconds until the thermocouple warms up.
4. Once the pilot light is lit and stable, switch the control knob to “ON” to restart the burner.

Frequently asked questions

Your water heater questions, answered.

Why does my water heater pilot light keep going out?

This could be happening for several reasons, including a dirty or faulty thermocouple, a clogged pilot orifice, or a malfunctioning gas control valve. Drafts in the area or air in the gas line could also extinguish the flame. You’ll need to clean the affected parts or replace them if they’re damaged in order to solve the problem.

How do I reset my water heater pilot light?

NOTE: Always follow the manufacturer’s instructions for resetting your specific water heater pilot light. 

To reset the water heater pilot light, turn the gas control knob to the “OFF” position and wait a few minutes. Then, switch the knob to “PILOT” and use a long lighter to ignite the pilot light while holding down the control knob for 30-60 seconds. Afterward, set the gas valve to “ON” to relight the burner. 

How do I know if my thermocouple is bad on my water heater?

Signs of a bad thermocouple include the water heater pilot light going out frequently or not staying lit at all. If the thermocouple is dirty, bent, or damaged, it won’t detect the flame, which can prevent the pilot light from staying on.

Can I replace a water heater pilot light on my own?

Yes, you can replace the pilot light assembly on your own, but it’s important to follow all safety precautions. Make sure the gas is turned off before attempting any repairs. 

We’re here to help

Thanks for reading! We hope this guide helped you got your water heater working like a charm. Got more repairs on your to-do list? Explore our other guides and videos to keep the fixes rolling. For parts, grab your model number and head to AppliancePartsPros.com to place an order. You can also chat with our team, check out our blog and more. Make sure to hit the subscribe button on YouTube and follow us on Facebook, X and Instagram!