How to Respond If You Smell Gas in Your Home

Why this matters

Natural gas and propane have no smell of their own. Your utility or propane supplier adds an odorant so that a leak announces itself, and the smell it gives is usually described as rotten eggs or sulfur. When you smell it in the house, the gas has already built up enough to reach your nose, and the only thing between that and a fire is that nothing has lit it yet. The right response is short, it is the same every time, and almost all of it is about what you do not touch.

If you smell gas right now: do not touch any light switch, phone or flame. Get everyone out through the nearest door, leave that door open, and call the gas utility's emergency number or 911 once you are well away from the house. Read the rest later.

Step 1: Touch nothing that could make a spark

Leave every switch exactly as it is: light switches (on or off), the thermostat, appliance controls, the doorbell, the garage door opener, and any phone, landline or cell. Do not light a match, a lighter or a candle, and do not smoke. If you came in through an attached garage, do not start the car.

Why: a gas leak only becomes a fire or an explosion when something ignites it. Most switches make a tiny spark inside when they open or close, and that is enough. Turning a light off is just as risky as turning it on. If a flashlight is already on, keep it on; if it is off, leave it off.

What breaks if you skip it: the reflex to flip on the basement light so you can see where the smell is coming from is exactly the action this step exists to stop.

Step 2: Get everyone out, now

Everyone in the house, children and pets included, goes out through the nearest door. Do not stop to gather things, change clothes or find shoes unless they are right by the door. If someone cannot walk out, tell the dispatcher in Step 4 exactly where they are; do not go back in for them yourself.

Why: you cannot tell how much gas is in the air by smell. A faint smell in one room can sit next to a much heavier pocket in another, and the people inside are what you are protecting.

Step 3: Leave the door open behind you

Leave the door you went out through standing open. Do not walk around the house opening windows.

Why: an open door lets some gas start to escape without anyone staying inside to do it. Opening windows room by room means spending minutes in the place you are trying to leave.

Step 4: Call from a distance

Walk far enough that you no longer smell gas at all: across the street, a neighbor's house, the end of the block. Then call. The gas utility's emergency number is printed on your bill and often on a sticker at the meter; if you do not have it, call 911 and they will reach the utility. Gas utilities answer odor calls around the clock and treat them as emergencies.

Here is what the call usually sounds like:

UTILITY: Gas emergency line. Where are you calling
         about?
CALLER:  412 Alder Road. I smell gas inside. We are
         all outside now.
UTILITY: Is anyone hurt, dizzy or feeling sick?
CALLER:  No. Two adults, one child, one dog, all out.
UTILITY: Where is the smell strongest?
CALLER:  At the basement stairs, near the water
         heater. Strong when I opened the door.
UTILITY: Did anyone switch anything on or off?
CALLER:  No. The front door is open. Nothing else.
UTILITY: Good. Stay outside and away from the house.
         Do not go back in. A crew is on the way.
CALLER:  Should I shut the gas off at the meter?
UTILITY: No. Leave the meter alone. The crew will.
UTILITY: What number can we reach you at?
CALLER:  This one.

Call 911 instead of, or as well as, the utility if anyone is dizzy, has a headache or is nauseous, if you hear a loud hissing or roaring, or if there is any fire.

Why from a distance: a cell phone is a small battery-powered device, and used well away from the house it is no risk at all. Used inside, it is one more possible spark. Distance also keeps you safe if the worst happens while you are waiting.

Step 5: Wait for the utility, and stay out until they say so

Stay at your meeting spot and keep others away from the house, including neighbors who come over to help. Do not go back in to check, even if the smell outside fades. When the crew arrives, tell them what you told the dispatcher, and let them decide when anyone goes back inside.

Why you do not look for the leak

Every instinct says find it and fix it. Here is why that instinct is wrong this time.

• You would be standing in the gas. Walking from appliance to appliance sniffing for the strongest spot means spending the most time exactly where the concentration is highest.
• Your nose cannot measure. Smell tells you gas is present, not how much. The crew carries a combustible gas detector that reads the concentration and finds the leak point without anyone guessing.
• Your nose stops working. After a few minutes in an odor, the sense of smell dulls. The house can seem to be clearing while it is not.
• Fixing it is a pro's job. Tightening a fitting or swapping a connector on a gas line is work for a plumber, gas fitter or heating contractor, licensed where your state or locality licenses gas work; which trade depends on where you live. A fitting tightened by feel can leak worse the next day.

The same goes for the meter valve. It takes a wrench, and once it is closed every pilot light in the house goes out, so turning gas back on means someone checking every appliance and relighting each one. That is why most utilities ask you to leave the meter to them unless they instruct you otherwise on the call.

What happens when the crew arrives

Using the example call above: a crew arrives at 412 Alder Road. They read the air at the open door and in the basement, and find the leak at the flexible connector feeding the water heater. They close the shutoff valve at the water heater, which stops the leak while leaving the furnace and range in service, ventilate the basement, and re-check until the readings clear. They attach a red tag to the water heater saying it must not be used until it is repaired. Then they tell the family it is safe to go back inside.

That evening the house has heat and a stove but no hot water. The next morning a licensed plumber replaces the connector, leak-checks the new joint, opens the valve and relights the water heater. The family writes down the date, the crew's finding, the tag, and the plumber's repair in their house records. See related: Your House Records File and What Goes In It.

What would have changed that night:

• The leak was upstream of every appliance valve, on the house piping or at the meter. The crew closes the meter valve and the whole house goes without gas until a licensed pro repairs the piping. Only the utility or that pro turns the meter back on and relights the pilots.
• Someone felt sick. The 911 call happens first and the medical side moves first. The rest of the night is the same.
• The family had tried to find the leak first. Two people would have spent several minutes in the basement next to the source, which is the one outcome the whole procedure exists to prevent.

When relighting is yours, and when it is not

After any gas emergency, relighting is not yours. If the utility closed the meter or an appliance valve, or left a tag, the appliance stays off until the utility or a licensed pro restores it. Do not remove a tag. See related: What the Tags and Stickers a Tech Leaves Behind Mean.

A pilot that went out on its own, with no gas smell at all, is a different situation. Many older water heaters and furnaces have relighting instructions on a label on the appliance, and some homeowners follow them. If you smell gas at any point while doing it, stop, leave the controls where they are, get out and call. If the pilot will not stay lit, or goes out again, that is a call for a licensed pro, not a second try.

Situations that change the first move

A faint whiff for a second when a burner lights. A gas range can release a brief puff of odor in the instant before the burner catches. If it is gone within a few seconds and does not come back, that is usually normal. A smell that lingers, grows, or is there when nothing is lit is a leak: start at Step 1. If you are not sure which you have, treat it as a leak.

The smell is outside. A smell near the meter, along the yard where the service line runs, or bubbling in a puddle, still goes to the utility. Move away from it before calling, and keep people and cars away. Dead patches of grass along the line or a hissing sound are worth mentioning on the call.

You have propane. Propane is heavier than air, so it settles low: basements, crawlspaces, floor level. Call your propane supplier's emergency number or 911 from a distance. Propane suppliers' safety guidance often says to close the main valve on the tank if you can reach it safely outdoors; follow your own supplier's instructions, and never go back into the house to do it. After a propane leak, the supplier or a licensed pro leak-checks the system before anything is relit. Propane's odor can also fade, especially in a new tank, which is one reason some households add a gas alarm.

You cannot smell well. Some people's sense of smell is weak, and it often weakens with age, colds and some medications. A plug-in gas alarm listed for natural gas or propane, mounted where its instructions say (high for natural gas, low for propane), adds a second warning. It is a backup to your nose and to the rules above, not a replacement.

A carbon monoxide alarm is sounding. That is a different gas and a different alarm, with its own steps. See related: How to Respond When Your Carbon Monoxide Alarm Goes Off.

On a calm day, before you ever need this

• Find the gas utility's emergency number and put it in your phone and on the inside of a kitchen cabinet door.
• Know where your meter or propane tank is, so you can tell the crew. See related: Your Home's Shutoffs: Water, Gas and Electric.
• Pick an outside meeting spot the whole household knows.
• Walk your household through the five steps once, including the rule that nobody flips a switch.

References

• See related: When to Stop and Call a Licensed Pro Around the House
• See related: Smells in the House and What Each One Might Mean
• See related: Your Home's Shutoffs: Water, Gas and Electric
• See related: What the Tags and Stickers a Tech Leaves Behind Mean
• Your gas utility's or propane supplier's published gas safety instructions, which govern the meter and tank valves in your area