Gas Smell in the House? Leave First, Then Make These Calls
A strong rotten-egg smell, a hissing sound, or feeling dizzy means one thing: leave the house immediately, do not touch any switch or phone on the way out, and call 911 and your gas utility from outside. A faint, fleeting smell can be a pilot light out or a bumped stove knob, but you confirm that only after the air is clear. Here is how to tell the difference and what repairs cost once the line is safe.
Non-emergency questions
For an active emergency, 911 and your gas utility come first. For everything that can wait (repairs, replacements, questions), a licensed pro is on the line.
(855) 000-0000New installs, replacements & repairs · No obligation
Safety first: if you smell gas, see water near electrical outlets or your panel, or sewage is contacting living areas, get people clear first. For a gas smell, leave and call 911 or your gas utility's emergency line before anything on this page.
- !A strong or growing rotten-egg smell anywhere in the house: leave NOW, take everyone with you
- !A hissing or whistling sound near a gas line, appliance or the meter
- !A strip of dead, yellowed or wilting vegetation over a buried gas line outside
- !Anyone feels dizzy, nauseous, has a headache, or trouble breathing
- !Do not flip switches, use phones, or start anything inside: any spark is a risk. Call 911 and the gas utility from OUTSIDE
If any of these apply, get everyone out, then call 911 or your gas utility's emergency line. This is an emergency response, not a contractor call.
- ✓Only for a faint, fleeting smell with no hissing and no symptoms: check whether a pilot light has gone out on a water heater, furnace or stove
- ✓Check the stove and cooktop knobs: a bumped knob can release unburned gas without a flame. Turn all knobs fully off and ventilate
- ✓Open windows and doors to air the space, then step outside and let it clear before deciding anything
- ✓Distinguish the smell: gas mercaptan is sharp rotten egg or sulfur; a drain smell is more like rotten sewage and points to a sewer-gas issue, not a gas leak
- ✓If the faint smell returns after airing out, stop checking and treat it as a leak: leave and call from outside
- →A pilot light keeps going out or will not relight after you ventilate and reset it
- →A faint gas smell recurs day after day even with no obvious source
- →Aging appliance connectors or flex lines you can see (cracked, corroded, or decades old)
- →The utility shut off your gas and a licensed plumber now needs to repair and pressure-test your side
- →Any appliance connection that smells of gas when the appliance runs
Not an emergency? Talk it through with a pro.
For repairs, appliance hookups and plumbing questions: calls are answered around the clock by licensed plumbing pros. For an active emergency, 911 comes first.
Call & describe the job
Tell us what you need: a new install, a replacement, or something that started leaking.
Get matched on the line
You are connected with a local licensed plumbing pro who serves your area.
Compare your numbers
Use the ranges on this page to sanity-check the quote before you commit.
Why gas smells like rotten eggs
Natural gas and propane are naturally odorless. Utilities add a chemical called mercaptan specifically so a leak announces itself, and it is engineered to smell unmistakably foul: sharp rotten egg or sulfur, the kind of smell you notice instantly. That smell is a safety feature doing its job. If you catch even a whiff of it strengthening, the design intent is for you to leave, not investigate.
Because mercaptan is so distinct, your nose is a reliable first detector. The trap is that a faint, one-time whiff (a pilot that puffed out, a knob nudged for a second) smells the same as the start of a real leak. The rule that keeps you safe is simple: a strong or growing smell is an evacuation, every time, no exceptions for "let me just check the stove first."
The evacuation drill
When the smell is strong, move, do not troubleshoot. Get every person and pet out of the house through the nearest door. On the way out, do not flip a light switch on or off, do not unplug anything, do not use a phone or a garage door opener, and do not relight a pilot: each of those can throw a spark, and a spark in a gas-filled room is the whole danger. Leave a door open behind you if it is easy, but do not go back for it.
Once you are outside and well away from the house, call 911 and then your gas utility, whose emergency line answers 24/7. They respond at no charge to the meter, shut the gas off, and confirm when the home is safe to re-enter. Do not go back in until they clear it. If the leak turns out to be on your side of the meter, the repair becomes yours, and a corroded line may need a per-foot replacement like a new gas line install.
The faint-smell diagnostic tree
A faint, fleeting smell with no hissing, no symptoms and no second occurrence usually traces to one of a few harmless events. The most common is a pilot light that blew out: a water heater, furnace or older stove pilot can puff out in a draft, releasing a brief whiff of unburned gas before the safety valve closes. A stove or cooktop knob bumped just off its detent does the same thing without lighting. Turn every knob fully off, ventilate, and the smell should clear and stay gone.
One smell people confuse with a gas leak is sewer gas. A gas leak smells like sharp rotten egg or sulfur and tends to be near an appliance or pipe; a sewer smell is more like rotten sewage and rises from a drain, a toilet, or a dry trap. If the odor is coming from a sink or floor drain rather than an appliance, it is almost certainly a drain issue, covered in our guide to a sewer smell in the house. When in doubt between the two, treat it as gas and step outside first.
What the repairs cost
Once the utility has made the home safe and the leak is on your side of the meter, a licensed plumber takes over. Most fixes are at an accessible point (an aging appliance connector, a valve, a loose joint) and run $150 – $800 to locate, repair and re-test, the typical range for this kind of work. Aging connections are the usual cause, so a plumber often replaces nearby connectors together rather than returning for the next one.
A buried or in-wall line costs more because access is the work, and a recurring leak can mean the line needs replacement rather than a patch. Every repair ends with a pressure test that proves the line holds. If the utility shut you off, restoring service bundles a permit and re-light. Full pricing, including who pays for what, is on our gas leak repair cost breakdown. This is licensed-only work; there is no homeowner-safe version of repairing a gas line.
Carbon monoxide is the silent sibling
A gas leak you can smell is the danger you can detect. Carbon monoxide is the one you cannot: it is colorless, odorless, and produced when a gas appliance burns incompletely, often from a cracked heat exchanger, a blocked flue, or a starved burner. The symptoms (headache, dizziness, nausea) mimic the flu and can appear with no smell at all.
Mercaptan does not protect you from CO, so every home with gas appliances needs working carbon monoxide detectors, on each level and near sleeping areas, with batteries checked twice a year. If a CO alarm sounds, treat it like the gas drill: get everyone outside into fresh air and call 911. A persistent pilot that will not stay lit can also signal a combustion problem worth a professional look, covered in our pilot light troubleshooting guide.
Ready to get it handled?
One call, no obligation. Describe the job and compare the quote against the ranges above.