Short answer: Leave now and take everyone with you. Do not turn lights or appliances on or off, do not use a phone, light a match or start a car near the smell. Once you are outside and away from the house, call 911 or your gas company. The American Gas Association notes that utilities add an odorant called mercaptan so leaking natural gas smells like rotten eggs (PHMSA describes it as skunk-like). Do not try to find or fix the leak yourself.
Quick diagnosis
| What you notice | Most likely cause | What to check | Call a pro? |
|---|---|---|---|
| Strong rotten-egg or skunk smell indoors | Gas leak | Leave the house now | 911 or gas company, from outside |
| Hissing sound near a gas line or appliance | Escaping gas | Leave; do not touch valves | 911 or gas company |
| Faint smell near the stove right after lighting a burner | Brief release while igniting | If it lingers, treat it as a leak | If it lingers |
| Smell outside near the meter or in the yard | Leak at the meter or underground line | Move away; call from a distance | Gas company |
| Dead patch of grass or bubbling in puddles over a gas line | Underground leak | Stay away from the area | Gas company |
| CO alarm sounding, headache or nausea, no smell | Carbon monoxide (it has no odor) | Get outside, call 911 | Yes, now |
Do this, in this order
- Get everyone out of the house, including pets.
- Do not create a spark: no light switches, appliances, doorbells, phones, lighters or matches, and do not start a car in an attached garage.
- Move well away from the house, upwind if you can.
- From there, call 911 or your gas company’s emergency number. Leaks can be reported anonymously, and the American Gas Association says to always call.
- Do not go back inside until the gas company or firefighters say it is safe.
What not to do
- Do not search for the leak or try to fix it.
- Do not operate gas valves; PHMSA advises leaving them to responders.
- Do not unplug anything or open an automatic garage door.
- Do not try to put out a gas fire.
Propane homes
Propane is also odorized to smell like rotten eggs, but the gas company is your propane supplier. Leave first, then call the supplier or 911 from outside. Have the system checked by a qualified technician before using it again.
Gas leak or carbon monoxide?
A gas leak usually smells. Carbon monoxide, from a furnace, water heater or stove that is not burning or venting properly, has no smell. CPSC recommends CO alarms on every level of the home and outside sleeping areas, tested monthly; if one sounds, get outside and call 911.
After the emergency
If the gas company finds the leak is on your side of the meter, the repair is yours: hire a licensed plumber or gas line technician, and follow the gas company’s instructions before using gas again. HomeGuide warns never to attempt DIY gas line repairs.
When to call a professional
- Any time you smell gas indoors: leave and call from outside.
- The gas company shuts off service and asks for a licensed repair.
- A gas appliance flame burns yellow, or soot appears around it.
- You want a whole-house pressure test after a renovation or an old line.
What it usually costs
HomeGuide (2026) lists minor gas leak repairs at about $150 to $500, appliance connector repairs at $100 to $400, valve replacement at $250 to $750 and replacing sections of gas line at $400 to $1,000, with underground repairs at $1,500 or more. Pressure tests run about $75 to $150, and emergency calls typically cost 1.5 to 2 times more.
Frequently asked questions
What does a gas leak smell like?
Like rotten eggs or a skunk. Utilities add the odorant mercaptan so leaks are easy to notice.
Should I open the windows if I smell gas?
Getting out comes first. Do not stay inside to open windows or look for the source.
Who do I call for a gas leak, 911 or the gas company?
Either, from outside and away from the house. Many gas companies have a 24-hour emergency line on the bill.
Is a small gas smell near the stove normal?
A brief whiff when a burner lights can happen. A smell that stays, or one with the stove off, should be treated as a leak.
Related problems
Sources
- American Gas Association: Using natural gas safely
- U.S. PHMSA: Pipeline leak recognition and what to do
- U.S. CPSC: Winter weather tips to prevent fires and carbon monoxide poisoning (2026)
- HomeGuide: Gas leak repair cost (2026)
This guide is general information, not a substitute for an inspection by a licensed professional. See our disclaimer.