Relighting or confirming a pilot light on a gas water heater is a common maintenance task. Knowing how long to hold the pilot light and what to do if it won’t stay lit can prevent gas leaks and cold water scenarios. This guide covers safe relighting steps, typical holding times, troubleshooting, and when to call a professional. It focuses on standard residential gas water heaters used in the United States and emphasizes safety and accuracy.

Safety Considerations Before Relighting

Before attempting to relight the pilot, ensure the area is well ventilated and free of gas smells. If a strong gas odor is detected, evacuate the area and contact the gas utility or emergency services. Turn the gas control knob to the “Off” position, wait several minutes for any accumulated gas to clear, and then proceed with relighting according to the manufacturer’s instructions. Use caution around standing pilot lights and avoid using flames or sparks near the appliance.

How The Pilot Light And Thermocouple Work

A gas water heater pilot light provides a small flame that keeps the thermocouple heated. The thermocouple sends a signal to the gas valve, allowing main burner gas to flow if the pilot is lit. If the thermocouple cools, the valve shuts off gas to prevent a potentially dangerous situation. Holding the pilot light button long enough ensures the thermocouple becomes hot enough to establish a stable flame.

Typical Holding Time For The Pilot Light

Relighting after a flameout: Hold the pilot button and light once the spark or match is near the pilot opening. Keep holding for 20 to 60 seconds after ignition to ensure the thermocouple warms sufficiently.
Stable ignition: If the flame remains lit and the thermocouple is hot, you can release the button after the recommended hold period and observe operation.
No ignition or flame goes out: If the pilot never stays lit, turn the gas off, wait, and repeat the relighting procedure. If it still fails, the thermocouple or gas valve may need replacement.

Important note: Always refer to the specific manufacturer’s instructions for your model, as some units may have different hold times or safety procedures. If in doubt, seek professional service rather than forcing the pilot to stay lit.

Step-By-Step Relighting Procedure

Turn the thermostat to Off and wait at least 5 minutes to clear any gas buildup.
Set the gas control knob to Off and remove the access panel to locate the pilot assembly.
Turn the knob to Pilot and press and hold the reset button or pilot button, depending on the model.
While holding the button, use a long lighter or the built-in igniter to ignite the pilot flame at the pilot opening.
Continue to hold the pilot button for 20–60 seconds after ignition to ensure the thermocouple heats up.
Release the button gradually and observe that the pilot flame remains lit. If it goes out, repeat the steps once more.
Replace the access panel, turn the gas control knob to On, and set the thermostat to the desired temperature.

What To Do If The Pilot Won’t Stay Lit

Several issues can prevent a pilot from staying lit. Common causes include a faulty thermocouple, a dirty pilot orifice, or a malfunctioning gas control valve. If the thermocouple is dirty or misaligned, clean or adjust it following the manufacturer’s guidance. If cleaning doesn’t help, the thermocouple or the gas valve may need replacement. Do not force the pilot to stay lit for extended periods, as this can cause gas leaks or overheating.

When To Call A Professional

The pilot consistently goes out after the hold period, even after cleaning the thermocouple and verifying gas flow.
There is a persistent gas odor or hissing sound near the heater.
You are uncomfortable performing DIY gas appliance maintenance or the unit is older than 15–20 years.
The flame is yellow or bubbling, indicating incomplete combustion or dirt in the burner.

Common Troubleshooting Tips

Flame color: A healthy pilot flame should be blue with a tiny yellow tip. A yellow or orange flame indicates incomplete combustion or sooting.
Gas smell: If you smell gas, evacuate and contact the utility or emergency services immediately.
No ignition: Ensure the gas supply is on and the pilot assembly is clean and properly aligned.
Thermocouple damage: A bent, cracked, or corroded thermocouple may fail to sense heat and shut off the gas valve.

Additional Tips For Maintaining A Gas Water Heater

Schedule annual professional inspections to verify venting, gas connections, and burner efficiency.
Flushing the tank every 12–24 months can extend heater life and improve efficiency.
Replace old thermostats and sensors that show signs of wear or error codes.