Does a water heater leak gas if the pilot light is out?

Author: Aubree Conn  |  Last update: Thursday, June 18, 2026

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.

Does gas leak when pilot light goes out on water heater?

Lack of Hot Water or Warm Air

In many systems, a broken pilot light will prevent the appliance from working at all. This is a safety precaution to prevent a buildup of excess gas in the unit, which can be dangerous for you and your family, potentially leading to a gas leak.

Does gas come out if pilot light goes out?

This valve operates automatically and shuts off gas flow as soon as the pilot goes out, preventing any risks of excessive gas buildup. That said, even the failsafe system can malfunction, so any time your pilot is out, be sure to carefully check for any strong gas odors, like the scent of sulfur or rotten eggs.

What happens if a water heater pilot light goes out?

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.

How do I know if my gas water heater is leaking gas?

To check if your gas valve is leaking, turn off the gas supply to the water heater and remove the access panel. Look for any signs of gas leaks, such as hissing sounds or the smell of gas. If you notice any signs of a gas leak, call a professional plumber to address the issue immediately.

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Is it okay to smell a little gas from a water heater?

While a faint gas smell might not necessarily indicate a serious issue, a strong or persistent odor demands attention. It's important to differentiate between a normal, intermittent odor and a potential gas leak.

What are the symptoms of a gas leak?

Natural Gas Leak Physical Symptoms
  • Ringing in your ears.
  • A reduced appetite.
  • Pain in the chest.
  • Nosebleeds.
  • Blistering or pale skin.
  • Flu-like symptoms.
  • Dizziness.
  • Breathing difficulties.

Is it safe in the house if the pilot light goes out on the water heater?

The thermocouple's job is to shut a gas safety valve if the pilot light goes out. That's important because gas is always being supplied to the pilot to keep the flame lit. 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.

How to tell if gas is on a water heater?

Another way to identify your water heater type is to look for a pilot (flame). To do this, you will need to locate the access panel on the unit and see if you can spot a bluish flame – if you do, then you are seeing a gas-powered unit in action.

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

Water Heater Pilot Light Replacement

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.

Is it safe to leave the pilot light off?

Typically, extinguishing the pilot light in the summer is safe and often sound practice. However, several factors must be considered, including safety, energy efficiency, and cost.

Can there be a gas leak if the gas is turned off?

Yes, if either the shutoff valve or the “city side” of the gas line is faulty. (Obviously there will not be a leak inside the house, but there can still be gas escaping into the local environment.)

Should I smell gas after lighting pilot light?

Note that it is totally normal on automatic pilots (pilots that do NOT stay lit all the time) to smell a little natural gas when they are first turned on. A little gas will escape as the pilot and burners light on your heat or appliance.

Does gas still flow if the pilot light goes out?

A pilot light may need to be re-lit from time to time after being extinguished on purpose or by accident. If it is accidentally extinguished, there exists a danger that the gas used to keep the flame lit will continue to vent, possibly into the living space.

Does turning off the gas to water heater turn off pilot light?

The first step is to turn off the gas supply valve. You can typically find the valve near the base of the water heater and turn it off by rotating it 90 degrees until it's perpendicular to the gas line. Afterward, you'll have to turn off the pilot light.

Should I turn off the gas water heater if it leaking?

If you have figured out that the leak is actually coming from your water heater, then you should turn off the water to your tank. Most hot water tanks have a shutoff valve on the cold inlet pipes. Gate-style valves: A gate valve looks like a little wheel.

Can you smell gas from a water heater?

Although an electronic igniter should light the burner almost immediately, a small amount of gas may flow before the burner lights. As such, there are times when you may notice a very faint gas smell when the water heater first turns on and starts heating. However, the gas smell should dissipate almost immediately.

How much does a gas water heater cost per month?

Gas water heaters are generally less expensive to operate than electric water heaters. Based on national averages, electric water heaters cost $42 a month. Gas water heaters average $30. Of course, your water usage habits and water heater setting also affect monthly energy costs.

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.

Do I need to turn off gas to flush a water heater?

Step 1: Turn Off the Heating Source

You should turn off your water heater's heat source before flushing it to reduce the risk of scalds.

What happens if water heater pilot light goes out?

Your thermocouple senses when your pilot light is burning. The tip of the thermocouple sits over the pilot flame, generating a voltage that keeps the gas valve open. If it senses that your water heater pilot light keeps going out, the thermocouple will shift off the gas supply to the heater.

How long does it take for a gas leak to affect you?

Severe leaks can cause this problem in just five minutes. The EPA states that exposure to concentrations of nine ppm or more for eight hours is enough to produce harmful health effects for at-risk individuals. Exit the property and call 911 if you suspect your home has a gas leak.

Can you stay in a house with a gas leak?

Here's what you should DO if you smell gas: DO leave the home, building, or area of the suspected leak. Get to a safe area as quickly as possible. After leaving your home, DO call the 24-hour emergency number for Peoples at 1-800-400-4271, or call your local emergency response number.

Will a carbon monoxide detector detect a gas leak?

No, carbon monoxide (CO) alarms cannot detect natural gas leaks. They are designed to detect the presence of carbon monoxide, a poisonous gas formed during incomplete combustion of fuels like oil, gas, propane, and wood.

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