Gas Line Safety: The Signs of a Gas Leak You Shouldn't Ignore

If you smell gas right now, stop reading and act. A suspected natural gas leak is a life-safety emergency, not a maintenance call. Get everyone — including pets — out of the house, leave the door open behind you, and from a safe distance outside call 911 and PG&E. Do not flip a switch, touch a garage-door opener, or light anything. Call a licensed plumber after the home is safe and the utility has cleared it.

With that said, most calls we take aren't full-blown emergencies — they're homeowners who noticed something "off" and were smart enough to ask. This guide walks through the signs of a gas leak, what to do the moment you suspect one, what causes leaks in older East Contra Costa homes, and why gas-line work is one of the few plumbing jobs you should never DIY. I'm Jesse Delgado, owner of Flow Pro Plumbing here in Brentwood, and our crews run these diagnostics across the East Bay every week.

What does a gas leak smell like, and what are the warning signs?

The clearest sign of a natural gas leak is the smell of rotten eggs or sulfur. Natural gas is naturally odorless, so utilities add a chemical called mercaptan specifically so you can detect a leak by smell. That rotten-egg odor is the warning system working — treat it as real every single time. Beyond the smell, watch for these signs:

• Rotten-egg or sulfur odor near an appliance, a wall, or out in the yard.
• A hissing or whistling sound close to a gas line, meter, or appliance connector.
• Dead or dying vegetation in a line over the path of a buried gas line, when the rest of the lawn is healthy — escaping gas displaces oxygen at the roots.
• An unexplained spike in your gas bill with no change in how much you're using.
• Physical symptoms indoors — headaches, dizziness, nausea, fatigue, or trouble breathing that ease once you step outside.
• A pilot light that keeps going out, or visible dust blowing from a spot in the ground near the line.

If you notice even one of these, treat it seriously. You don't need to confirm all six — one credible sign is enough to get out and call for help. When in doubt, leave and let a professional verify it's safe.

What should you do the moment you suspect a gas leak?

Get out first, then call from outside — in that order. Your safety is worth far more than your property, and the wrong action indoors can turn a small leak into a serious event. Here is exactly what to do:

• Leave immediately. Get every person and pet out of the building and move well away from it.
• Don't create a spark. Don't flip light switches on or off, unplug anything, use the phone indoors, start a car in the garage, or operate the garage door. Any of these can ignite gas.
• Don't light a flame. No lighters, matches, candles, or stoves.
• Leave the door open as you exit if you can do it without delay — but don't go searching for the source or opening windows throughout the house.
• Call 911 and PG&E from a safe distance — a neighbor's house or down the street. The gas utility will shut off service and confirm when it's safe to return.
• Don't turn the gas back on yourself. Only the utility or a licensed professional should restore service after a leak.

Once the home is cleared and safe, that's when a licensed plumber comes in to find the source, repair or replace the affected line, pressure-test it, and get it back up to code. If it's the middle of the night or a holiday, that's exactly what our 24/7 emergency plumbing line is for.

What causes gas leaks in East Contra Costa homes?

Most leaks we find around Brentwood, Antioch, Oakley, and the wider East Bay come down to age, corrosion, or work that was never done to code. The Delta climate and our older housing stock both play a part. The usual culprits:

• Corroded older pipe. Aging black steel and galvanized gas lines rust from the inside out, eventually opening pinholes at threaded joints.
• Failed appliance connectors. The flexible connector behind a range, dryer, or water heater can crack or loosen over years of vibration and heat.
• Damage from digging. Landscaping, fence posts, or a remodel that nicked a buried line — a common reason to call 811 before you dig.
• Unpermitted or DIY work. A gas line teed off for a new range or fire pit without the right pipe, sizing, or sealant — and without a permit or pressure test.
• Ground movement. Settling soil or seismic activity can stress rigid pipe and loosen fittings over time.

Knowing the cause matters because it drives the fix. A single bad connector is a quick repair; widespread corrosion on a 40-year-old line is a different conversation — which is exactly what we cover in gas line repair vs. replacement.

Why does licensed gas-line work matter so much?

Gas-line work is regulated for a reason: a mistake doesn't drip, it ignites. In California, gas piping work generally requires a permit, a pressure test, and an inspection, and the gas utility has to clear the system before relighting. Skipping those steps is where DIY and unlicensed "handyman" work goes wrong — undersized pipe, the wrong sealant on tapered threads, no leak test, and no inspection trail. The failure modes are serious: an unsafe home, a failed real-estate inspection, voided insurance, and a redo that costs more than doing it right the first time.

Flow Pro Plumbing is CSLB C-36 licensed and insured, and we pull the permit and handle the pressure test and inspection as part of the job. If you want the plain-English version of when a permit is required and who issues it, see gas line permit requirements and our overview of plumbing permits and code compliance in East Contra Costa County. Unfamiliar with a term like "mercaptan" or "pressure test"? Our plumbing glossary breaks them down.

How Flow Pro Plumbing handles a suspected gas leak

When you call us about gas, we treat it as urgent. Our crews carry combustible-gas detectors, isolate and test sections of the system to pinpoint the source, and walk you through what we find before any work starts — that white-glove, no-surprises approach is why we've earned a 4.9-star rating across 900+ Google reviews, Best of Oakley 2021, and Best of Houzz 2018. Our technicians train every week, so the person at your door is current on code and equipment. We've served East Contra Costa and the Tri-Valley since 2017, and you can see every community we cover on our service-area map.

This is also a great argument for not waiting until something smells wrong. A scheduled gas-line and appliance-connection check is part of our maintenance plans — the cheapest leak is the one we catch before it starts.

What to do next: If you suspect a leak right now, get out and call 911 and PG&E first. Once you're safe, contact Flow Pro Plumbing to find and fix the source, or learn more about our licensed gas line services and around-the-clock emergency plumbing. You can always start at our Learning Center for more guides like this one.

Frequently Asked Questions

Is a gas leak always dangerous, even a small one?

Treat every suspected leak as dangerous. Natural gas is flammable and can displace oxygen, and a "small" leak can build up in an enclosed space. The safe move is always the same: leave, call 911 and PG&E from outside, and let professionals confirm it's safe before you go back in.

I smell gas faintly near my stove. Should I still evacuate?

If you notice a brief whiff right when a burner is lighting and it clears immediately, that can be normal. A smell that lingers, gets stronger, or shows up away from the stove is not — leave and call for help. When you're unsure, err on the side of getting out. A false alarm costs you nothing; ignoring a real leak can cost everything.

Who do I call first — 911, the gas company, or a plumber?

From outside the home, call 911 and PG&E first; they handle the immediate hazard and shut off the gas. A licensed plumber like Flow Pro Plumbing comes in afterward to locate the leak, make the repair, pressure-test the line, and get the system back to code so service can be safely restored.

Can I use a carbon monoxide detector to find a gas leak?

No — those are different hazards. A carbon monoxide (CO) detector senses CO, a byproduct of incomplete combustion, not raw natural gas. Every home should have working CO alarms, but for a suspected gas leak rely on the rotten-egg odor, hissing, and the other signs above, and call the utility. A pro will use a calibrated combustible-gas detector to confirm.

Does Flow Pro Plumbing offer 24/7 gas-line emergency service?

Yes. We answer the phone around the clock for gas and other plumbing emergencies across East Contra Costa County and the Tri-Valley. Once your home is safe and the utility has done its part, reach out to us and we'll get a licensed technician on the way.