Smell Rotten Eggs? 7 Signs of a Gas Leak and What to Do Immediately

If you suspect a gas leak, leave immediately, avoid anything that could spark, and call 911 and your gas utility from a safe location.

A strange smell in the kitchen. An unusual hissing sound near the stove. A patch of grass outside that suddenly starts dying. These may seem like unrelated household problems, but they can be warning signs of a gas leak.

Natural gas is commonly used to power stoves, water heaters, furnaces, clothes dryers, and other household appliances. Although it is a convenient energy source, a leak can create a serious fire or explosion hazard.

Recognizing the signs of a gas leak early can help you respond before the situation becomes more dangerous. The most familiar warning is a rotten egg or sulfur-like smell, but you may also notice unusual sounds, damaged connections, or changes around outdoor gas lines.

This guide covers seven warning signs, what to do if you suspect a leak, common mistakes to avoid, and how to keep your home’s gas system safer.

7 Warning Signs of a Gas Leak You Should Never Ignore

A gas leak does not always announce itself in the same way. Depending on where the leak occurs and how much gas escapes, you may notice a smell, hear a sound, or see changes around your property.

Here are seven signs worth recognizing.

1. A Rotten Egg or Sulfur-Like Smell

One of the most recognizable signs of a natural gas leak is an odor similar to rotten eggs, sulfur, or a strong skunk-like smell.

Natural gas is naturally odorless. Gas utilities add an odorant, commonly mercaptan, to make it easier to detect a potential leak.

If you notice an unfamiliar sulfur-like odor in your kitchen, laundry room, basement, utility area, or near a gas appliance, take it seriously.

Do not assume the smell will disappear on its own or that it is simply coming from a drain or household cleaning product. If you suspect natural gas, leave the area and report it from a safe location.

2. Hissing, Whistling, or Roaring Sounds

Gas escaping through a damaged pipe, loose connection, or faulty component may produce an unusual sound.

Depending on the leak, you might hear:

• A faint hiss near a gas pipe or appliance.
• A high-pitched whistle around a connection.
• A louder blowing or roaring noise near a damaged gas line.

The sound may be easier to notice in a quiet room, basement, utility area, or outdoors near the gas meter.

Do not move closer to investigate where the sound is coming from. If you suspect a leak, leave the area immediately.

3. Bubbles in Standing Water

Unexpected bubbling in a puddle, wet ground, or another standing-water area can indicate escaping gas from an underground line.

You might notice continuous bubbles appearing in one spot, even when there is no obvious reason for the water to move.

This sign is particularly important around outdoor gas piping or underground utility routes.

Do not touch the water, dig into the ground, or attempt to identify the source. Move away and report the suspected leak to the appropriate emergency service or utility company.

4. Dirt or Dust Blowing From the Ground

If you notice dirt, dust, or debris moving upward from a specific point in your yard without a clear explanation, an underground gas leak is one possible cause.

Escaping gas can disturb loose soil around a damaged underground pipe. You may see:

• Dust rising from a small opening in the ground.
• Soil moving or blowing without an obvious wind source.
• A localized area of disturbed ground near a gas line.

Do not approach the area to inspect it. Keep people and pets away and contact emergency responders from a safe location.

5. Dead or Discolored Plants Near a Gas Line

A patch of grass, shrubs, or other vegetation that suddenly dies or changes color may be worth investigating, particularly if the surrounding plants look healthy.

An underground gas leak can affect vegetation above or near a damaged pipe. You may notice an unusual dry or discolored patch in an otherwise green lawn.

This sign alone does not confirm a gas leak. Weather conditions, plant disease, soil problems, and watering issues can also damage vegetation. However, unexplained changes near a gas pipeline should not be ignored, especially when accompanied by other warning signs.

6. Damaged Gas Pipes or Appliance Connections

Visible damage around a gas appliance or pipe connection can indicate a potential leak.

Pay attention to signs such as:

• A visibly damaged or disconnected pipe.
• A loose-looking connection near a gas appliance.
• Corrosion or physical damage around exposed piping.
• A damaged gas meter or connection point.

Never touch, tighten, disconnect, or test a suspicious connection yourself. Even if you cannot smell gas, visible damage to gas equipment should be reported to the gas utility or an appropriate professional.

If you suspect an active leak, evacuate first and call from a safe location.

7. Unusual Changes in Gas Appliance Operation

Changes in the way gas appliances operate can sometimes indicate a problem with the gas supply or appliance system.

For example, you may notice an unusually high or low burner flame, an appliance that does not operate as expected, or an unexpected interruption in gas supply.

These changes do not automatically mean there is a leak. Appliance faults, supply issues, and other mechanical problems can produce similar symptoms.

However, if unusual appliance behavior occurs alongside a gas odor, hissing sound, or visible damage, treat the situation as a possible gas emergency. Do not continue using the appliance to see whether the problem goes away.

What to Do If You Suspect a Gas Leak at Home

Knowing what to do matters just as much as recognizing the warning signs. When a gas leak is suspected, your priority is to get everyone away from the potential danger.

Follow these steps.

Step 1: Leave the Building Immediately

Stop what you are doing and evacuate everyone from the affected building or area. Take children, older adults, and pets with you if you can do so without delaying your exit.

Do not stay inside to search for the source, collect belongings, or investigate the smell.

If you are outdoors and suspect a leak, move away from the area. If possible, move upwind and stay clear of the suspected source.

Step 2: Avoid Anything That Could Create a Spark

Do not operate electrical equipment or anything that could create an ignition source.

Avoid:

• Turning lights or electrical switches on or off.
• Using a mobile phone or landline inside the affected area.
• Plugging in or unplugging electrical devices.
• Operating a garage door opener.
• Starting a vehicle near the suspected leak.
• Lighting matches, candles, or lighters.
• Smoking or using an open flame.

Do not stop to open windows, operate appliances, or shut off valves. Leave the area first.

Step 3: Call 911 and Your Gas Utility From a Safe Location

Once you are well away from the suspected leak, call 911 and report the situation. Contact your gas utility’s emergency number as well.

Explain what you noticed, where the suspected leak may be, and whether anyone may be affected.

Do not assume someone else has already reported it. Follow the instructions given by emergency responders and utility personnel.

Step 4: Keep Others Away From the Area

If you can do so without approaching the suspected leak or delaying your evacuation, warn others to stay away.

Do not let anyone re-enter the building or approach the affected area to investigate.

Step 5: Wait for Clearance Before Returning

Do not go back inside just because the smell has disappeared.

Emergency responders or utility personnel must assess the situation and confirm that the area is safe. Follow their instructions before re-entering or using gas appliances again.

What NOT to Do During a Suspected Gas Leak

Some common reactions can make a gas emergency more dangerous. Avoid these mistakes:

The safest response is simple: leave, stay away, and call for help from a safe location.

Natural Gas Leak vs. Carbon Monoxide: Are They the Same?

No. Natural gas leaks and carbon monoxide exposure are two different hazards, although both can be associated with fuel-burning equipment.

Carbon monoxide can be produced when fuel-burning appliances do not operate or vent properly. A CO alarm does not detect a natural gas leak, and a natural gas detector should not be treated as a substitute for a CO alarm.

Homes with fuel-burning appliances should have appropriate carbon monoxide alarms installed and maintained according to the manufacturer’s instructions and local requirements.

If a CO alarm sounds or people experience possible carbon monoxide poisoning symptoms, move outdoors immediately and call 911. Do not re-enter until authorities say it is safe.

Can You Smell Every Gas Leak?

No. Although the familiar rotten egg odor is an important warning sign, you should not rely on your sense of smell alone.

Natural gas supplied to homes is commonly odorized to make leaks easier to recognize. However, odor may be less noticeable in certain conditions. Strong competing smells and reduced ability to detect odors can also make it harder to recognize a problem.

This is why recognizing visual and sound-related warning signs matters.

A natural gas detector designed for the type of gas used in your home can provide an additional layer of detection. Choose a suitable device, install it according to its instructions, and maintain it as recommended.

Most importantly, never ignore a suspected leak just because you cannot smell gas.

How to Reduce the Risk of Gas Leaks at Home

You cannot eliminate every possible cause of a gas leak, but sensible maintenance and careful use of household equipment can help reduce avoidable risks.

Keep Gas Appliances Properly Maintained

Have gas-powered appliances checked and maintained according to their manufacturer’s recommendations. Pay attention to unusual operating behavior, visible damage, or changes in performance.

If the appliance is a furnace that is not heating properly, see our guide to furnace repair problems and costs.

Do Not Ignore Damaged Connections

If you notice visible damage around a gas pipe, meter, or appliance connection, do not attempt to fix it yourself. Report the issue to your gas utility or an appropriate professional.

If you suspect an active leak, evacuate and follow emergency procedures rather than arranging routine maintenance. For non-urgent repairs after the area is confirmed safe, you can book a gas line repair with a vetted local plumber.

Be Careful During Home Renovations

Construction, drilling, excavation, and landscaping can damage gas piping if the location of underground or concealed utilities is not identified beforehand.

Before digging or undertaking work that could affect buried utilities in the United States, contact 811 to have underground utility lines marked.

Know Where to Find Emergency Contact Information

Keep your gas utility’s emergency contact information somewhere accessible outside the immediate gas appliance area. Make sure household members know to call from a safe location if they suspect a leak.

For other urgent household problems, see our guide to handling home repair emergencies.

Consider Appropriate Gas Detectors

A natural gas detector can provide an additional warning if combustible gas is detected. Choose a detector suitable for your fuel type and follow its installation and maintenance instructions.

A detector is a backup safety measure, not a replacement for recognizing warning signs or responding immediately to a suspected leak.

When Should You Contact a Gas Line Professional?

Not every gas-related issue is an emergency, but problems involving damaged piping, an appliance connection, or planned gas line modifications should not be treated as DIY projects.

For non-emergency work, a qualified professional can assess the gas piping and determine whether installation or other work is required.

If you are planning a new appliance connection, relocating an existing gas line, or extending piping to another part of your home, you can review the gas line installation and repair service available through InstaService.

InstaService connects homeowners with independent vetted service professionals. The appropriate service and project scope depend on the property and location. On the service page, the listed inclusions are assessment and inspection of existing gas lines, installation of new gas piping and systems (parts are charged extra), and testing and commissioning of gas lines. Procurement of municipal permits and approvals, repair and maintenance of gas-powered appliances, and landscaping and cosmetic site restoration are listed as excluded.

Planning a new connection and want to know what it costs? Read our gas line installation cost guide.

Frequently Asked Questions About Gas Line Leaks

Final Takeaway: Know the Signs Before You Need Them

A rotten egg smell, an unexpected hissing sound, bubbling water, or unexplained changes around your yard may be more than ordinary household issues. They can be warning signs of a gas leak.

The most important thing to remember is that you should never try to investigate or repair a suspected leak yourself. Leave the area, avoid anything that could create a spark, and contact emergency responders and your gas utility from a safe location.

Share this guide with your family, neighbors, and anyone who uses gas appliances at home. Recognizing the warning signs and knowing what to do can make a critical difference during an emergency.

This article is for general safety education and does not replace emergency instructions from local authorities or your gas utility. Always follow official guidance for your location. InstaService is a technology platform that connects homeowners with independent vetted local service professionals and does not employ or directly provide the professionals performing the work.