Short Answer
What does a gas leak smell like? Rotten eggs or sulfur. Natural gas has no smell of its own, so utilities add an odorant called mercaptan to make leaks easy to notice. If you smell it, leave the house on foot, then call CenterPoint Energy at 888-876-5786 and 911 from a safe distance.
What does a gas leak smell like? In most homes, it is a sharp rotten egg or sulfur odor that does not belong there. Repipe Solutions is a licensed Houston plumbing company that repairs home gas piping. This guide covers what the smell means, the other signs and symptoms of a gas leak, false alarms, and who fixes what once the gas company has made your home safe.
If you smell gas right now, stop reading and leave the house.
Smell Gas Right Now? Do This First
These steps come from CenterPoint Energy, the natural gas utility for most of Greater Houston, and its natural gas leak safety page.
- Leave immediately on foot. Take people and pets with you. Do not stop to gather belongings.
- Do not create a spark. Do not flip light switches on or off, use your cell phone inside, light a match or lighter, or start a car.
- Do not look for the leak and do not try to shut off the gas meter unless you have been trained to do it.
- Get well away from the house. CenterPoint advises moving at least 350 feet from the building.
- Call from outside. Call CenterPoint at 888-876-5786 and call 911. Do not assume a neighbor has already reported it. CenterPoint’s safety page also lists 713-659-2111 for reporting a gas leak. If another company supplies your gas, use the emergency number on your gas bill.
- Stay out until emergency crews tell you it is safe to go back in.
CenterPoint responds to gas leak reports at no charge. Some guides say to open windows first. CenterPoint’s advice is not to spend time on windows: just get out.
What Does a Gas Leak Smell Like?
What does gas smell like when it is leaking? PSE&G explains that an odorant called mercaptan is added before the gas reaches customers, which gives it an unpleasant rotten egg or sulfur smell.
Does a gas leak smell like rotten eggs every time? Usually. Constellation notes that the stronger the smell, the more likely you have a leak.
A faint smell still counts. A slow leak at a fitting behind a range or dryer may give off only a light odor in one room. Treat it the same as a strong one.
Can You Smell a Gas Leak Every Time?
Not always, so never rely on smell alone.
- Nose fatigue. Peoples Gas says that even a short exposure to the odorant can cause nasal fatigue, where a person stops smelling it.
- Masking odors. CenterPoint notes that cooking smells and damp, musty, or chemical odors can hide the smell of gas.
- A weak sense of smell. Colds, sinus problems, and allergies can all reduce your ability to pick it up, according to Peoples Gas.
- Odor fade. In rare cases, the odorant itself can weaken, for example when gas passes through certain soils or into new piping.
Signs of a Gas Leak in a House
The smell is the main sign, but it is not the only one. Utilities list these other signs of a gas leak:
| Sign | What it looks or sounds like |
|---|---|
| Sound | Hissing, whistling, or roaring near a gas line, meter, or appliance, even with the appliance off |
| Bubbles | Bubbling in puddles, mud, or standing water over a buried line |
| Dead plants | A ring or patch of dead grass in an otherwise green yard, or houseplants dying for no clear reason |
| Blowing dirt or mist | Blowing dirt, a dry spot, or a white mist near a gas line |
Sources: CenterPoint Energy, PSE&G, Peoples Gas, and Constellation. Constellation explains that gas in the soil starves plant roots of oxygen.
A gas bill that jumps without a change in how you use gas can also point to a leak. Any one of these signs is reason to leave and call CenterPoint.
Gas Leak Symptoms: How Leaking Gas Can Make You Feel
CenterPoint notes that natural gas itself is non-toxic, but it is still a hazard to breathe. High concentrations in an enclosed space can cause dizziness or make it hard to breathe. Constellation says the symptoms come from being deprived of oxygen, vary with how much gas and how long you are exposed, and may include:
- Headaches, sometimes severe
- Dizziness and fatigue
- Nausea
- Irregular breathing or chest pain
- Blurred vision, confusion, or trouble concentrating
- Loss of consciousness in serious cases
If you or anyone in the house has these signs and symptoms of a gas leak, get everyone outside into fresh air, call 911, and see a doctor.
Gas Leak or Carbon Monoxide?
The symptoms overlap. A gas leak is unburned gas escaping from a pipe or fitting, and it usually smells. Carbon monoxide (CO) is produced when gas or other fuel burns poorly, for example in a furnace, water heater, or range that is not working or venting right. The CDC describes CO as an odorless, colorless gas and lists headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion as its most common symptoms, often described as flu-like.
| Natural gas leak | Carbon monoxide | |
|---|---|---|
| Smell | Rotten eggs or sulfur (added odorant) | None |
| Main danger | Fire or explosion, and low oxygen in closed spaces | Poisoning |
| Detected by | Your nose, or a natural gas (methane) detector | A CO alarm only |
| What to do | Leave, then call CenterPoint and 911 from outside | Get to fresh air and call 911 |
The CPSC lists headache, fatigue, shortness of breath, nausea, and dizziness as signs of low to moderate CO poisoning,. If symptoms ease when you leave the house and return when you come back, take that seriously.
House Smells Like Gas but No Leak?
Call CenterPoint first, every time. CenterPoint says every gas smell should be investigated, even if only your house smells and your neighbors do not. Only after the utility has checked and found no gas leak should you look at these other causes of a rotten egg smell.
- Sewer gas from a dry drain. Sewer gas contains hydrogen sulfide, which the CDC’s ATSDR describes as a colorless gas that smells like rotten eggs. The water sitting in each drain trap is what keeps that gas out of the room, and the Texas IRC 2021 notes that a trap seal can be lost to evaporation. A guest shower, floor drain, or sink nobody uses can dry out and let the smell in. Running water into the drain refills the trap.
- Smelly hot water. If the odor shows up when you run hot water, the water heater may be the source. Bradford White explains that the rotten egg smell needs three things: sulfur, hydrogen, and bacteria. The magnesium anode rod in a tank heater gives off hydrogen, and sulfur-reducing bacteria turn sulfate in the water into hydrogen sulfide. The fix is usually a different anode rod and chlorinating the tank, a job for a plumber.
- A burner left on. A stove knob bumped to on without a flame lets gas out. That is a real gas release, so treat it as a leak.
ATSDR also notes that people lose the ability to smell hydrogen sulfide after a few minutes at high levels, so a fading smell is not proof the problem is gone.
Are Older Houses More Prone to Gas Leaks?
Age is a real factor. CenterPoint lists aging or corroded pipes and equipment among the common causes of gas leaks. In Houston, homes built before the 1990s often still have galvanized steel gas pipe, which rusts from within and stays out of sight until a fitting gives way. The local clay soil adds stress: it expands in wet weather and contracts in drought, which can bend or pull apart buried lines near a slab or driveway.
If your home is older and still has its original piping, our guide on how long gas lines last explains the lifespan of each pipe material, and gas line repair vs replacement covers when a single fix is enough.
Gas Detectors: A Backup for Your Nose
- Natural gas detectors. Peoples Gas says residential methane detectors listed by Underwriters Laboratories (UL) add a layer of safety when the odor alone may not warn you. CenterPoint also suggests having one installed.
- Carbon monoxide alarms. A CO alarm does not detect a natural gas leak, as Constellation points out. It warns you when an appliance burns fuel poorly. The CPSC recommends CO alarms on every level of the home and outside sleeping areas.
- Yearly service. The CDC recommends having your heating system, water heater, and other gas appliances serviced by a qualified technician every year.
Who Fixes a Gas Leak: CenterPoint or a Plumber?
Both, in order. CenterPoint responds to the emergency, makes the area safe, and shuts off gas when needed. It maintains the service line up to and including your meter. Everything after the meter, the house piping and the branches to your appliances, belongs to the homeowner and needs a licensed plumber. In Texas, gas piping is plumbing work under the state plumbing license.
After the utility has made your home safe, our licensed plumbers find the leak, repair the piping, pull the city permit, and run the pressure test needed for CenterPoint to turn service back on. A single fitting or joint repair runs about $150 to $700 with us, and leak detection about $150 to $500. Full pricing is on our gas line repair and installation page. Adding an appliance? See gas line installation cost.
When to Call a Plumber
- Call CenterPoint and 911 first for any gas smell, hissing, or other sign of a leak. A plumber is not the first call.
- Call a licensed plumber once the utility has shut off or tagged your gas and the pipe on the homeowner’s side of the meter needs repair.
- Call a plumber if CenterPoint finds no gas leak but a rotten egg smell keeps coming from your drains or hot water.
Our 24/7 emergency plumbing service is available nights, weekends, and holidays. For other urgent problems, see what counts as a plumbing emergency and our guide to emergency plumber cost.
Frequently Asked Questions
Does a gas leak always smell like rotten eggs?
Usually, because of the added mercaptan. But nose fatigue, other odors, a cold, or rare odor fade can make a leak hard to smell. Hissing, bubbles, or dead grass are warning signs on their own.
Will a carbon monoxide detector go off for a gas leak?
No. A CO alarm senses carbon monoxide from poor combustion, not unburned natural gas. For leaks you need a UL-listed natural gas (methane) detector.
Should I open the windows if I smell gas?
No. CenterPoint advises against spending time on windows. Leave right away and call from a safe distance.
Why does only my house smell like gas when my neighbors’ houses do not?
The leak may be on your own piping or at your meter. CenterPoint says to treat it as an emergency and call it in either way.
Who pays to fix a gas leak inside my house?
CenterPoint responds to leak reports at no charge and handles its equipment up to and including the meter. Repairs to piping and appliances on your side of the meter are the homeowner’s cost and need a licensed plumber.
Need Gas Line Repair in Houston?
Once CenterPoint has made your home safe, Repipe Solutions finds and repairs the leak, pulls the permit, and handles the pressure test so your gas can be turned back on. Estimates are free with no trip charge. See our gas line repair services in Houston or contact Repipe Solutions to schedule a visit.
Featured photo: “Gas meters” by ivva via Openverse, licensed under CC BY-SA 2.0, converted to WebP and shared under the same license.