Pilot Light Won't Stay Lit on a Gas Water Heater

Likely causes, most common first

1. Worn or failed thermocouple
2. Dirty or clogged pilot orifice or assembly
3. Pilot not held long enough while lighting (the unit's instructions say how long)
4. Failing gas control valve
5. Venting or draft problems that blow the flame out
6. Low or interrupted gas supply

What you can safely check

1. Read the lighting instructions on the unit label and follow them exactly.
2. Hold the control as the label says while lighting, for the time it says.
3. Check that nothing is blocking air around the heater and the room has fresh air.
4. If it lights but goes out again after you let go, stop. Do not repeat it many times.

What not to do

• Do not try to light a pilot if you smell gas.
• Do not remove or bypass the thermocouple or safety devices.
• Do not use a flame near the unit if you smell gas.
• Do not keep relighting a pilot that keeps going out.

When to call a professional

Call if the pilot goes out again after relighting, you smell gas, the burner will not fire, or you see soot or a yellow, lazy flame. These can point to venting or combustion problems.

Related service: water heater repair.