Smell Gas Near Your Furnace? What to Do First

By Proair Air Conditioning Services, CSLB C-20 License #776028. Published October 30, 2026. Updated October 30, 2026.

Smell gas near your furnace? Leave, then call

This is the whole plan. Do it in this order, and do not add steps.

1. 1

   Get everyone out

   Go now, using the nearest door. Take people and pets, and leave everything else behind.

2. 2

   Change nothing on the way

   Do not touch light switches, the thermostat or appliances. Do not light anything.

3. 3

   Get to a safe location

   Walk well away from the building, past the point where you can smell gas.

4. 4

   Call from there

   Call 911 or SoCalGas at 1-800-427-2200. SoCalGas answers at any hour. Call 911 first if anyone is hurt or the danger looks serious.

5. 5

   Stay out

   Do not go back inside until the responders tell you it is safe.

Long Beach has its own gas system. Long Beach Utilities customers call its emergency line at (562) 570-2140, or 911.

What should you not do if you smell gas?

SoCalGas is direct on this. Anything that can make a spark or a flame can ignite gas, and that includes ordinary things you touch without thinking.

• Do not smoke, or light a match, candle or lighter.
• Do not turn lights or appliances on or off.
• Do not start a vehicle or motorized equipment nearby.
• Do not use any device that could spark while you are inside. Make your call from the safe location.
• Do not try to control the leak or repair a pipe, fitting or meter.

Why no troubleshooting, not even a quick look?

You cannot see a gas leak, and you cannot measure one with your nose. A furnace sits in a closet, attic or garage, where gas can collect, and it has its own ignition source that can fire when the thermostat calls for heat.

That is why you should not adjust the thermostat, open the furnace door or go looking for the shutoff valve at the unit. Testing fittings is a job for later, done by a qualified person with the right equipment, after the house has been cleared.

What about the gas meter?

Leaving comes first. Do not delay your exit to find a wrench. SoCalGas says to shut a meter off only when you smell gas, hear it escaping or see other signs of a leak, and only if it is safe to do so. The person on the phone can tell you what to do from where you are standing.

Once a meter is off, leave it off. SoCalGas says to call them to turn the gas back on and relight pilots, and the piping and appliances must be checked first.

Gas, carbon monoxide or something else?

You do not need to work this out. SoCalGas warns that you may not smell a leak at all if your sense of smell is reduced or another odor masks it, so treat any doubt as a real leak.

If a carbon monoxide alarm goes off

A steady alarm is real until responders say otherwise. CPSC’s order is to move outside, call 911 or the fire department, then count heads. Do not look for the source, and do not go back in until responders give permission. A single chirp usually points to a low battery, so replace it. Anyone with symptoms should see a doctor and say they suspect carbon monoxide.

What happens after the all-clear?

The responder decides what stays on. If the problem is at the furnace, the gas to that appliance may be shut off and the unit left out of service until it is repaired. Do not relight it or turn it back on yourself, and follow what you are told.

• Ask what was found and where, and write it down.
• Ask which appliances are safe to use now.
• Use a contractor with an active C-20 license for the furnace, and check it on the CSLB site.
• Get the repair scope in writing, and ask whether the work needs a city permit.
• If you rent, tell your landlord or property manager the same day.

From there it is a normal repair. Our emergency furnace repair page and furnace repair page explain how we diagnose the unit and give you the price before work begins. We work in Huntington Park, South Gate and the surrounding cities during posted hours.

Afterward, keep up with a yearly furnace safety check, keep stored items away from the unit and test your CO alarms, which California law requires in homes with fuel-burning appliances.

What usually causes a gas smell at a furnace?

This list is for reading after the house is cleared. It is not a home inspection, and none of these are yours to check.

• A fitting at the unit: joints near the gas valve can loosen or wear.
• A failing gas valve: the part that meters gas to the burners can fail or leak.
• An old flexible connector: in the 1990s CPSC warned that older uncoated brass connectors can break, and said moving the appliance to look can cause the failure.
• A neighboring appliance: a water heater in the same closet or garage can be the real source.

A sound repair finds the exact leak point, fixes it and retests that joint. Then the furnace runs through a full heating cycle while someone watches it. Ask to hear what was found and what was tested.

Who pays for a leak past the meter?

Usually the property side does. SoCalGas says owners, managers, tenants and occupants must maintain the customer-owned lines on their side of the meter, which includes piping from the meter to your appliances. It also says a qualified plumbing or heating contractor can help find, inspect and repair buried lines. Ask the responder which side of the meter the problem is on and write down the answer. Renters should pass that note to the landlord, because the lease decides who arranges the repair.

Leave first, fix it later

One rule covers all of this: people out, call from outside, stay out until responders clear the house. A fitting can always be fixed tomorrow. Your first call is 911 or SoCalGas, and an HVAC company comes after that. Once you have the all-clear and the furnace is still off, call us. We will find the fault, explain it plainly, give you the price before work starts and test the system before we leave.