How to Light a Water Heater Pilot
Updated February 20, 2026
Relight a gas water heater pilot light safely. Takes 5 minutes once you know the sequence. Covers both manual and electronic ignition models.
Overview
Pilot light went out? No hot water. This is one of the most common water heater calls, and it almost never requires a plumber. A draft, a gas supply interruption, or a dirty thermocouple can extinguish the pilot. Relighting takes 5 minutes. The process varies slightly between manual ignition (hold a flame to the pilot) and electronic ignition (push a button), but the basic sequence is the same: gas off, wait, set to pilot, ignite, hold, verify.
What You'll Need
Safety First
- If you smell strong gas (rotten egg odor) when you approach the water heater, do NOT attempt to light the pilot. Leave the area, do not flip any switches, and call your gas company from outside.
- Wait at least 5 full minutes after turning the gas valve to OFF before attempting to light. This lets any accumulated gas dissipate. Igniting accumulated gas can cause a flash or explosion.
Step-by-Step Instructions
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Turn the Gas Valve to OFF
Locate the gas control valve on the front of the water heater near the bottom. Turn the knob to the OFF position. Wait at least 5 minutes. This is not optional -- any accumulated gas needs time to dissipate. While you wait, locate the pilot assembly: look through the viewport window at the bottom of the tank. You should see a small metal tube (pilot tube) near the burner.
Tip: Use the waiting time to clean the viewport window with a rag. A dirty window makes it hard to see if the pilot is lit. -
Set to PILOT and Prepare to Ignite
After 5 minutes, turn the gas knob to PILOT. Press and hold the knob down (or press the separate pilot button if your model has one). This manually opens the gas line to the pilot tube only. You need to keep holding it while you ignite.
Tip: On some models you press the knob in while turning it to PILOT. On others, PILOT is a separate detent. Read the label on your water heater -- most have lighting instructions printed right on the unit. -
Ignite the Pilot
While holding the gas knob or pilot button down: Electronic ignition models -- press the igniter button (usually red or black, labeled IGNITE). You will hear a click. Look through the viewport for a small blue flame at the pilot tube. Click repeatedly if it does not light on the first try. Manual ignition models -- use a long-reach lighter or fireplace match. Insert it through the access opening at the bottom and hold the flame at the pilot tube tip while pressing the gas knob.
Tip: If the pilot will not light after 3-4 attempts, turn the knob back to OFF, wait 5 minutes again, and retry. If it still will not light, the pilot tube may be clogged or the gas supply may be off. -
Hold for 30-60 Seconds
Once the pilot is lit, keep holding the gas knob or pilot button for 30-60 seconds. This heats the thermocouple -- the safety sensor next to the pilot flame. The thermocouple must get hot enough to generate a voltage that tells the gas valve to stay open. If you release too early, the thermocouple is not hot enough and the pilot goes out immediately.
Tip: 60 seconds is safer than 30. A cold thermocouple takes time to heat up. If the pilot goes out when you release, hold longer on the next attempt -- up to 90 seconds. -
Release and Turn to ON
Slowly release the gas knob or pilot button. The pilot should stay lit. If it goes out, repeat from step 2 with a longer hold time. Once the pilot stays lit, turn the gas knob from PILOT to ON. Set the temperature dial to your desired setting (120 degrees recommended). You should hear the main burner ignite -- a whoosh or soft roar. Look through the viewport to confirm a blue flame across the burner.
Tip: If the pilot stays lit but the main burner does not ignite when you turn to ON, the gas valve may be faulty. This is a plumber or gas technician job. -
Verify and Monitor
Replace the access panel if you removed one. Check for hot water at a faucet in 20-30 minutes. If the pilot goes out again within hours or days, the thermocouple is likely failing and needs replacement. A pilot that lights but will not stay lit is the classic sign of a bad thermocouple.
Tip: Write down the water heater model number now while you are looking at it. If you need a thermocouple later, having the model number makes getting the right part much easier.
Pro Tips
- Pilot goes out repeatedly? 90% of the time it is the thermocouple. A $10-20 part that takes 15 minutes to replace.
- If the pilot flame is yellow or orange instead of blue, the pilot tube orifice is dirty. A yellow pilot does not heat the thermocouple properly. Clean the orifice with compressed air or a fine needle.
- Some newer water heaters do not have a standing pilot -- they use electronic ignition that lights only when heat is needed. These units have no pilot to relight. If there is no hot water, check the power source and error codes on the control panel.
- A drafty area can blow out a pilot. If your water heater is near an open window, exterior door, or in a garage with vehicle traffic, a draft shield may help.
- After relighting, check the gas line connections with soapy water. Brush it on every joint and watch for bubbles. Any bubbles mean a gas leak -- tighten or call a plumber.
When to Call a Pro
Call a plumber or gas technician if you smell strong gas and cannot identify the source, if the pilot will not light at all (possible gas supply issue or clogged pilot tube), if the pilot lights but goes out immediately every time (thermocouple or gas valve failure), if the main burner does not ignite after the pilot is lit, or if you see error codes on an electronic ignition model that you cannot clear.