Solved! What Does a Gas Leak Smell Like?

Learn how to detect the smell of natural gas and what to do in case of a gas leak.
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Q: I recently moved into a house with gas appliances. I purchased new smoke and carbon monoxide detectors, but I’m not sure what I need to detect gas leaks. What does a gas leak smell like, and what should I do if I notice a gas leak smell or gas leak symptoms?

A: An important question to ask first if you want to be able to detect gas leaks at home is what does gas smell like? If you have any propane-fueled equipment, you also want to ask what does propane smell like? Recognizing the smell of a gas leak helps you detect a potentially dangerous problem and take action as soon as possible. Both propane and natural gas are odorless, but in the interest of safety, gas companies add an odorant component called mercaptan to give gas a distinctive rotten egg smell.

Other than a strong gas smell in the house, signs of a gas leak include hissing sounds from the gas pipes, bubbles in standing water outside the home, suspicious plant deaths inside or around the home, unusual white mist or fog around the property, and lingering health effects. Use this guide to find out more about gas leak symptoms and answer the question: What does a gas leak smell like?

There are multiple ways to detect a natural gas leak at home.

People and animals require oxygen to live, but when gas begins flooding into the home from a cracked pipe, a leaking fireplace, or a damaged appliance, the gas actually can push oxygen out of the space due to the high density of natural gas and propane. As the oxygen percentage drops, you might experience physical symptoms of exposure to gas, including nausea, headaches, and trouble breathing.

If the situation worsens, you could actually pass out and suffocate, so it’s important to be able to recognize the signs of a gas leak. Gas leaks can be detected by scent, sight, and sound, so you can take immediate action as soon as you spot one of these telltale symptoms.

Rotten Egg Smell

Natural gas and propane are odorless substances, but when gas companies add mercaptan to the gas, it gives off a strong rotten egg or sulphuric scent. This distinctive smell is one of the most recognizable signs that you might have a gas leak in your home.

Hissing Noise

Whether the gas leak is coming from the pipes, valves, or connections to appliances, there is typically a hissing sound that the gas makes as it escapes the closed system. If you hear a hissing sound near your gas lines or any gas appliances, there might be a gas leak in the home.

what does a gas leak smell like air mist rising from deck

Mist, Fog, or Abnormal Airflow

Natural gas and propane are colorless, but if there is a high-pressure gas leak outdoors, this could cause a white mist or fog to appear. Similarly, high-pressure gas leaks might be “visible” if you spot dirt blowing out of the yard or air blowing across the plants when there isn’t a noticeable natural breeze outdoors.

RELATED: With Talks of Nationwide Bans, Are We Saying Goodbye to the Gas Stove?

Bubbles in Standing Water

The gas line that runs into the home can break down over time. If you notice that standing water near the home is inexplicably bubbling, then this could indicate that you have a gas leak. Contact the gas company to inspect the problem.

Dying Houseplants

Most plants, like most animals, require oxygen to live. A gas leak can displace the oxygen in the soil outside and in the air indoors, leading to suspicious plant death inside and outside the home. So, even if you have trouble keeping plants alive on the best of days, a cluster of dead plants might be a sign of a more serious issue.

Health Effects

Scents, sights, and sounds are the preferred methods for detecting gas leaks, but you might also find out about a gas leak by recognizing these physical symptoms of exposure to natural gas: headaches, dizziness, fatigue, nausea, irregular breathing, memory problems, loss of concentration, loss of consciousness, suffocation.

what does a gas leak smell like - plumber checking for leak in gas pipes

Act quickly if you detect a gas leak in the home.

A gas leak is a serious hazard to your health and to the safety of the home. Gas smells near an appliance might just indicate the pilot light has gone out or that the burner valve is open slightly, so make sure to check if this is the case before proceeding. If you detect a gas leak in the home that cannot be linked to an open burner or an extinguished pilot light, you need to take action immediately.

  1. Leave the area where you smell, hear, or see the gas leak.
  2. Call 911 or your local gas company for help.
  3. Don’t use any electrical equipment or lights that might create a spark, including matches, lighters, light switches, doorbells, thermostats, elevators, appliances, and telephones.
  4. Put out candles, fireplaces, and any other open flames.
  5. Don’t position or operate any vehicles or powered equipment near the suspected gas leak.
  6. Keep people and pets away from the area of the odor.
  7. If the odor is strong, leave the home immediately and ensure others remain outside the home.
  8. Do not operate the gas valve or go back into the home until the gas company says it is safe.
what does a gas leak smell like - explosive gas detector and monitor

Take preliminary steps to avoid gas leaks.

Preventing problems from occurring in the first place tends to be easier than responding to emergencies when they arise, so it’s a good idea to take some precautions to help avoid gas leaks.

  • Check your appliances, gas line connections, and gas shut-off valves regularly for any signs of wear.
  • Invest in a natural gas detector and monitor to help protect the home.
  • Use certified technicians for any work on gas appliances or the gas lines in the home.
  • Update old pipes, valves, appliances, or gas line connections that show signs of significant wear.
  • Make sure to keep the areas clean and unblocked around gas appliances and equipment for proper air flow.

RELATED: Electric Furnace vs. Gas—Which Heating System is Right for Your Home?

FAQ About What a Gas Leak Smells Like

Having more information in an emergency can help you make well-thought-out plans and take necessary steps to ensure your safety and the safety of anyone else in the home. Consider the answers to some of the most frequently asked questions about gas leaks to find out more about what a gas leak smells like and what to do if you smell natural gas in the house.

What does natural gas smell like?

Natural gas has no odor, which is why gas companies add mercaptan, an odorant, to give natural gas a distinctive rotten egg smell. If you detect the scent of rotten eggs, this could indicate that you have a gas leak in the house.

What should I do if I smell natural gas in my house?

A natural gas leak is a serious problem that needs to be handled as soon as possible. The most important first step is to leave the area where you detect a natural gas smell. Then call the local gas company immediately to inspect the problem.

What are the signs of natural gas poisoning?

With exposure to a slow gas leak, symptoms include dizziness, fatigue, nausea, headaches, and irregular breathing. If a person experiences high levels of natural gas exposure, it can lead to natural gas poisoning, which is characterized by more serious symptoms such as severe headaches, nausea, vomiting, fatigue, memory problems, loss of concentration, loss of consciousness, and suffocation.

How do I detect a gas leak?

Gas companies add odorants to natural gas to give it a rotten egg smell. There might be a gas leak in your home if you detect the scent of rotten eggs, hear hissing noises from the gas line, see bubbles in standing water outside the home, spot suspicious plant death near the home, or experience ongoing headaches, dizziness, fatigue, nausea, or irregular breathing.

Will a carbon monoxide detector detect a natural gas leak?

Smoke detectors and carbon monoxide detectors are important security measures to have in your home, but these devices are ineffective for detecting a natural gas leak. You will need to invest in a natural gas leak detection device to have an early warning if there is a problem.