Water Heater Pilot Will Not Stay Lit: Causes and Safe Fixes

A gas water heater whose pilot light keeps going out is a classic no-hot-water complaint. The pilot lights, burns for a moment, and then dies as soon as you release the control knob. Because a water heater burns gas, it pays to understand the safe checks and to respect where the professional line is. In most cases one specific part is to blame, and it is a common, well-understood failure.

Why the Pilot Will Not Stay Lit

Ordered from most to least likely.

• Dirty or failing thermocouple. This is the small metal probe that sits in the pilot flame. It senses heat and tells the gas valve it is safe to stay open. When it is dirty, bent, or worn out, it cannot confirm the flame, so the valve shuts the gas off. This is the number-one cause by a wide margin.
• Dirty pilot orifice. A clogged pilot tube produces a weak flame that cannot fully heat the thermocouple.
• Blocked air intake or flue. Dust or debris starves the flame of air, especially on sealed-combustion models.
• Faulty gas control valve. Less common, but a failed valve will not hold the pilot.
• Interrupted gas supply. A partially closed valve or an air bubble in a new tank.

Safe DIY Checks

These steps are safe if you follow the instructions printed on your water heater exactly.

1. Follow the lighting instructions on the unit's label precisely, holding the pilot knob for the full time specified, usually 30 to 60 seconds, before releasing. Releasing too early is the most common mistake.
2. Check for a strong blue flame. A weak or yellow pilot flame suggests a dirty orifice or an air problem.
3. Clear the air intake. Vacuum any dust from the intake screen at the base of the tank and keep the area around the heater free of clutter and lint.
4. Confirm the gas is on and that other gas appliances in the home are working.

When to Call a Licensed Pro, and Gas Safety

Gas water heaters demand caution. Call a licensed plumber or technician when:

• The pilot still will not stay lit after following the lighting steps, which usually means the thermocouple needs cleaning or replacement. This involves the gas control assembly and is best done by a professional.
• You suspect a failed gas control valve, a repair that opens the gas system.
• The flame is lifting, yellow, or sooty, which can signal a venting or combustion problem tied to carbon monoxide.

If you ever smell gas, do not try to light the pilot. Leave the home and call your gas utility or 911 from outside. Never relight repeatedly if you smell gas near the unit, and make sure a working carbon monoxide alarm is installed near any gas appliance. These are not optional precautions. Combustion problems can produce carbon monoxide, which is invisible and odorless, so an alarm is your family's safeguard.

Beyond safety, a water heater left without a pilot is a water heater not protecting itself from other faults, and a slow leak or a failing valve can turn into water damage or a flooded utility room if ignored.

How a Home Warranty Helps

Relighting the pilot is routine, but a failed thermocouple, a bad gas control valve, or a water heater that has broken down from normal wear and tear are covered mechanical failures. That is exactly what a home warranty is designed for. Instead of an unpredictable repair or replacement bill, you file a claim, pay a predictable flat service fee, and a licensed contractor diagnoses and repairs or replaces the covered unit. Flushing the tank once a year to control sediment helps it last longer and keeps your coverage in good standing.