What happens when a water heater pilot goes out?

Author: Erica Mayer  |  Last update: Tuesday, June 2, 2026

If the pilot light goes out, the gas will stop flowing and your unit will shut off. When heating is required, the gas control valve releases the gas into the main burner where the pilot light ignites the gas. Apart from lighting the main burner, the pilot light also provides warmth to the thermocouple.

What happens if the pilot light goes out on a water heater?

But if the pilot flame goes out, then the gas would still be released. After a while, the gas could collect in your home and become a health hazard. However, if there's an issue with the thermocouple, the safety valve will shut even if the flame is still lit. Use the schedule service button to get back in hot water!

Can I relight the pilot light by myself?

The Short Answer Is: It is generally safe for a homeowner to relight a furnace pilot light, as long as they follow proper precautions and guidelines. To do it yourself, first, turn off the furnace's gas supply and wait for a few minutes to allow any lingering gas to dissipate.

Will a water heater work without a pilot light?

None. First of all, most gas water heaters (no need to heat hot water) don't use pilot lights. They use an ignition system. Those that do need a pilot light that is just enough to light the burner when the gas valve is turned on by the thermostat.

How much does it cost to replace a pilot on a water heater?

Replacing the pilot light in a water heater should cost between $75 and $150. The pilot light might go out for various reasons on your gas water heater. It's rare for a heater to require a full replacement of the pilot light assembly.

FREE Fix! Pilot Light That WON'T STAY LIT on Water Heater

How difficult is it to replace a thermocouple?

Replacing a thermocouple is a relatively easy fix that can take less than two hours. This guide reviews how to replace a thermocouple to ensure gas appliances stay in good working order, as well as how to relight a pilot light.

Can I leave water heater on pilot mode?

Setting the system to “Vacation” or “Pilot” mode saves energy while also preventing damage to your water heater. It's a compromise between using no power at all and using a little bit of heat to avoid extensive damage to your system. So, as you can see, vacation mode is an essential feature of your water heater.

Can I flush my water heater without turning it off?

If the gas burner or electric heating elements come on during the flushing process, the water heater can be damaged, requiring repair or replacement. Some manufacturers will recommend turning the gas off completely during this process, others may recommend setting the gas valve to the “pilot” or “vacation” setting.

What is the most common problem with a water heater when the pilot light refuses to stay lit?

Lack of Combustible Air. Another reason your gas water heater pilot light won't stay lit could be due to not having enough combustible air. Your water heater requires air to keep the pilot light burning. Otherwise, the flame goes out.

Is it bad if the pilot light goes out?

Is It Dangerous if The Pilot Light Goes Out? The worry here is that when a pilot goes out, the gas valve that supplies the fuel for the pilot flame could still be pumping gas. This can mean a buildup of gas, and when the pilot is relit or relights itself, it could result in a very serious explosion.

Who to call for a water heater pilot light?

If you are having trouble getting your water heater pilot light on, or you can't get it to stay lit for long, rely on a plumbing professional for water heater repair, maintenance, and replacement services.

Will the gas company come light my pilot light?

Absolutely! We can send a gas service technician to light your pilot, and conduct a gas safety check of your gas fireplace or any other gas appliance to ensure your safety. You can schedule an appointment by logging into Your Account and selecting the Service Requests tab.

Will a gas leak happen if the pilot goes out on a water heater?

The thermocouple is a key component of any water heater. It's what closes the gas valve when the pilot light goes out. This safety feature is included with the valve so gas won't just leak out if the flame isn't there anymore.

How much to replace a thermocouple on a water heater?

The thermocouple is an apparatus that senses whether the pilot light is lit and triggers the gas control valve. Repairs typically cost about $150 to have it done professionally, though a new thermocouple itself only costs about $20 on average.

Why is my gas water heater not igniting?

If a gas water heater won't light, the first thing to check is to see if there is adequate gas pressure to the water heater. Next we would check the thermocouple/thermopile assembly. After checking that we would check the gas control valve to see if it's faulty.

What happens if you never flush your water heater?

-Reduced Efficiency: As scaling collects at the bottom of the tank, your water heater will become less effective at heating the water in the tank. -Corrosion: If your water heater goes long enough without a proper flush, you could also have corrosion attacking the tank itself, weakening its structural integrity.

Is it OK to turn off water but not water heater?

Else, if you have a full water tank, and you need to turn off the water for an issue unrelated to your water heater, then it really doesn't matter if you turn the water heater on or off.

What is the life expectancy of a water heater?

While today's water heaters are better designed than older models, they still require regular maintenance in order to prolong their lives. With regular inspection, draining, and flushing, you can expect a gas water heater to last anywhere from 8-12 years and an electric water heater to last anywhere from 10-15 years.

Will water heater work without pilot light?

Many newer water heaters no longer use a standing pilot light and instead use an automatic intermittent pilot or some other type of ignition system. However, if your unit has a standing pilot where there is always a constant flame, the unit won't be able to work until you can get the pilot to stay lit.

Why would water heater pilot go out?

The main reasons why a pilot light won't stay lit include: A dirty pilot light tube. Not enough gas or no gas at all. A faulty thermocouple.

Does turning off the pilot light turn off the gas?

In modern gas-fueled type water heaters feature valves that automatically close the supply of gas when the pilot light goes out. This involves a thermocouple device to detect if the pilot light is on via temperature and if it is not, then the voltage drops which in turn causes the gas valve to close.

Can I replace a water heater thermocouple myself?

It's easy to replace, and a new one costs $5 to $10. Rather than trying to unfasten the thermocouple inside the water heater's burning chamber, it's easier to remove the whole burner and thermocouple assembly.

Will the pilot light go out if the thermocouple is bad?

The thermocouple is a safety device designed to shut off the gas valve if the pilot light goes out. Although, if your thermocouple is old, worn, damaged, wrongly positioned, or malfunctioning, it could have wrongly shut off the gas valve and prevented your pilot light from staying lit.

How do I know if I need a new thermocouple?

When you have a thermocouple that is going bad on your water heater, the most obvious sign will be a pilot light that always seems to be going out. If you light the pilot light but then find it extinguished less than a week later, you'll need to closely examine the thermocouple.

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