You smell gas — what to do and what not to do

This article is for educational purposes only and is not a substitute for professional advice. Local codes, regulations, and best practices vary by region.

You smell gas. It’s an unmistakable rotten egg smell coming from somewhere in your house. Your instinct is to find it. Your instinct is wrong. There are very specific things you should do and very specific things you should not do when you smell gas. Getting this right matters for safety.

Natural gas itself is odorless. The rotten egg smell is an additive designed to alert you to a leak. If you smell gas in your home, you have a leak somewhere. This is serious but manageable if you follow the right steps.

What You Should Do Immediately

If you smell gas inside your home, follow this sequence:

First, do not search for the source. Do not light matches or lighters. Do not flip electrical switches. Do not use your phone inside the house. Any spark or ignition source could ignite gas. Leave these things alone.

Second, get everyone out of the house immediately. Do not linger. Do not gather belongings. Just leave. If someone is asleep, wake them and get them out. Tell them there’s a gas leak and you’re leaving now.

Third, once everyone is outside, call 911 or your gas utility’s emergency number from a phone outside the house. Give them your address and tell them you smell gas. The utility will send someone to investigate.

Fourth, do not re-enter the house. Wait for the utility company or emergency responders. Let them investigate and locate the leak. Your job is to get people away from potential danger.

What Not to Do

Never search the house for the source of the smell while people are inside. Never light anything. Never turn on or off electrical switches (including light switches, fans, or appliances). An electrical spark can ignite gas. Even your phone inside the house could be problematic because the battery could arc. Call from outside.

Never smoke. Never start your car inside the garage. Never do anything that could create heat or sparks.

Never assume the smell is coming from outside your house. If you smell gas, treat it as inside your house until proven otherwise.

Is This Serious?

Gas leaks range from minor (slowly leaking connection that you need to seal) to major (severed line that requires immediate evacuation). You cannot easily assess which one you have without professional equipment. The safe approach is to treat all gas smells as emergencies.

If you’re smelling gas constantly, it’s serious. If the smell is faint and intermittent, it might be less severe, but still requires professional investigation.

What the Utility Company Will Do

When you call, the utility company will send someone to your house. They have specialized equipment that detects gas leaks. They’ll systematically check all appliances, connections, and lines to locate the source. If they find a leak, they’ll either repair it or, if it’s severe, shut off your gas supply to the house until it’s fixed.

This service is usually free. The utility company wants to ensure safety in their service area. Finding and fixing the leak protects you and prevents danger.

Possible Sources of Gas Smell

Your furnace, water heater, stove, and dryer all use gas. Connections to these appliances can loosen or deteriorate, creating leaks. The utility company will check these first.

Sometimes a pilot light goes out on a gas appliance. When you reignite it, the gas smell happens temporarily. If the smell goes away after the pilot relights, that’s usually fine. If the smell persists, that’s a leak.

Occasionally people smell “gas” but what they’re smelling is mercaptan—the additive in natural gas—without actual gas being present. This can happen if you smell some additive residue. Real gas leaks produce consistent, unmistakable rotten egg smell.

After the Utility Company Investigates

If they find no leak, the smell might be coming from outside (a neighbor’s leak, a utility issue in the street). The utility company will determine this. You can go back inside safely.

If they find a leak, they’ll repair it or shut off your gas. For minor leaks (loose connections), repair is quick and inexpensive. For major leaks (severed lines, damaged appliances), you might need repair or replacement of equipment or lines.

For appliance-specific problems (pilot light issues, worn seals), the utility company might recommend calling a technician for that specific appliance. Some issues fall outside their service area.

What Happens If Gas Is Shut Off

If the utility company shuts off your gas because of a serious leak, your heat, hot water, and stove stop working. You need the problem fixed before they’ll turn it back on.

Do not attempt to relight pilot lights or turn gas back on yourself. Wait for professional service. Incorrect relight procedures can be dangerous.

Call the gas utility or the appropriate technician (furnace company, plumber, appliance repair) to fix the problem. Once it’s fixed, call the utility company back. They’ll send someone to verify the repair and turn gas back on.

This costs money for the repair, but it’s necessary for safety.

Preventing Gas Leaks

Gas appliances should be serviced annually by professionals. Regular service catches loose connections and worn seals before they become leaks.

If you notice gas smell intermittently or faintly, don’t wait. Call for service. Intermittent leaks often become serious leaks.

Know where your gas shutoff is located. Some people turn off gas during storms or disasters. Knowing how to do this safely is useful knowledge (though call your utility company if you’re unsure).

The Bottom Line

Smelling gas is a serious alert. It means something is wrong. The correct response is immediate evacuation and calling 911 or your gas utility. Do not search for the source. Do not create ignition sources. Let professionals investigate and fix it. This might result in your gas being temporarily shut off and repairs being needed, but safety comes first. A gas leak is not something to investigate yourself or delay addressing. Get people away from the smell and call for professional help immediately. This is the safe response.

© The Whole Home Guide