Signs of a Gas Leak in Your Home (And What to Do Immediately)

A natural gas leak in a home is a true emergency. Even a small leak can build to explosive concentrations in an enclosed space, and prolonged exposure causes health symptoms ranging from headaches to unconsciousness. Knowing the signs and the exact action sequence saves lives.

If you suspect a gas leak right now: leave the home immediately, call 911 and Atmos Energy at 1-866-322-8667 from outside, do not flip switches or use electronics, and do not return until cleared.

The Five Reliable Signs

1. Rotten-Egg Smell

Natural gas is odorless. The gas company adds mercaptan (which smells like rotten eggs, sulfur, or skunk) specifically so humans can smell leaks. Even a faint sulfur smell warrants investigation. A strong sulfur smell is an active emergency.

The smell may concentrate near:

Gas appliances (water heater, stove, dryer, furnace)
The gas meter outside
Under sinks or behind cabinets where gas lines run

2. Hissing Sound

A pressurized gas leak makes a faint hissing sound at the leak point. Listen near:

The gas meter
Around appliance connections
At wall-mounted gas valves

Air movement from HVAC can mimic this — listen carefully and rule out fans before assuming gas.

3. Physical Symptoms

Gas leak exposure causes:

Headache
Dizziness or lightheadedness
Nausea
Fatigue
Irritated eyes or throat
Difficulty breathing
Loss of consciousness (severe)

If multiple family members feel similar symptoms in the same parts of the house, especially symptoms that improve when outside, suspect gas exposure.

4. Dead or Discolored Vegetation Outside

A buried gas line leak in the yard kills plants directly above the leak. Look for:

A patch of brown grass in an otherwise green yard
Plants that have suddenly wilted
Discolored vegetation along a known gas line route

If a buried line leaks, the gas often migrates up through soil and into the home through the foundation slab.

5. Sudden Spike in Gas Bill

A leak that has been ongoing for weeks shows up on the bill. If your gas usage suddenly doubles or triples with no change in heating, cooking, or hot water habits, suspect a leak somewhere in the system.

What to Do IF You Suspect a Leak

The action sequence is non-negotiable:

Leave the home immediately. Take family and pets. Do not stop to gather belongings.
Do NOT flip light switches, plug or unplug anything, use phones, or use anything that could spark inside. Static electricity from these can ignite gas.
Leave doors open as you exit if possible — helps ventilate.
From OUTSIDE, away from the home, call 911.
Then call Atmos Energy at 1-866-322-8667. They will dispatch emergency response.
Do not re-enter until the gas company clears the home.
Once the gas company has secured the leak source, call our gas line repair service to repair and certify the line.

What NOT to Do

Do not try to find the leak yourself
Do not try to ventilate by opening the garage door (the motor can spark)
Do not strike a match or use a lighter to "smell" for gas
Do not test with soapy water until the gas is shut off
Do not call 911 from inside the home
Do not move the gas meter or its connections

How Atmos Energy Responds

Atmos Energy is the gas utility for most of the Round Rock service area. Their emergency response:

Dispatches a technician immediately (typically 30-60 minutes)
Uses gas detection equipment to locate the leak
If the leak is between the meter and the home, they may repair it
If the leak is in the home's gas piping (downstream of the meter), they shut off gas at the meter and inform you
Issues a red tag or formal lockout if there is unsafe equipment

Anything downstream of the meter is the homeowner's responsibility. That is when a licensed plumber repairs the leak and Atmos comes back to restore service.

Common Causes of Gas Leaks in Round Rock Homes

Aged connection fittings. Threaded gas fittings can loosen over time with thermal expansion and contraction. Common at water heater, range, and dryer connections.

Corroded buried gas line. Steel gas lines installed before the mid-1990s can corrode. CSST (corrugated stainless steel tubing) and modern polyethylene lines are more durable.

Foundation movement. Same clay soil shifts that cause slab leaks can stress buried gas lines.

Lightning strikes. Black iron gas pipe is a known lightning conductor. A strike can perforate the pipe. Modern bonded CSST minimizes this.

Appliance disconnects. A flex connector on a dryer or range can loosen if the appliance is moved.

Carbon Monoxide vs. Gas Leak

These are different problems:

Gas leak: raw natural gas escaping unburned. Smells like rotten eggs (the mercaptan additive). Explosive risk.

Carbon monoxide (CO): byproduct of incomplete combustion. Odorless, colorless. Cannot be smelled. CO comes from faulty combustion in furnaces, water heaters, gas ranges (especially when used as space heaters), and grills used indoors.

CO requires a different response: ventilate the home, get everyone outside, seek medical attention for symptoms. Install CO detectors on every floor — required by Texas code in new construction.

Prevention

Annual inspection. Have gas appliances and connections inspected annually. We include this in our service plans.

Modern materials. When repairing or extending gas lines, use CSST or polyethylene rather than old black iron where appropriate.

Quality flex connectors. Replace appliance flex connectors every 8-10 years, especially on dryers and ranges.

Carbon monoxide detectors. Plug-in or battery, one per floor, replace per manufacturer.

Know the smell. Familiarize your family with the rotten-egg odor. Some natural gas is less strongly scented than others — but mercaptan is unmistakable once you have smelled it.

Service

24/7 gas line repair throughout Round Rock, Cedar Park, Pflugerville, Georgetown, and Hutto. TSBPE-licensed gas work.