If you smell gas near the water heater, leave the house now. Don’t flip any light switches, don’t use your phone inside, and don’t try to turn off the gas yourself. Once you’re outside and a safe distance away, call SoCalGas at 1-800-427-2200, or 911 if there’s any danger to people or property. SoCalGas answers 24 hours a day. Then call a plumber. We handle the emergency plumbing side once the gas company has been out.
Natural gas has a rotten egg smell added so you’ll notice a leak. Treat that smell as gas until someone with a gas detector tells you otherwise.
What Not to Do if You Smell Gas Near the Water Heater
The California Public Utilities Commission lists what to avoid if you suspect a gas leak. Any of these can set off the gas.
- Don’t light a match, candle or lighter, and don’t smoke
- Don’t turn lights or appliances on or off, and don’t use the garage door opener
- Don’t use a phone inside the house
- Don’t try to stop the leak by turning valves or fixing anything
- Don’t start a car in the garage
The CPUC also says to listen. A gas leak can make anything from a quiet hiss to a loud roar.
And don’t relight the pilot on the water heater after you’ve smelled gas, even if it’s out. A pilot that went out may be the reason gas was escaping. Let the gas company check the area first, then have a plumber look at the heater.
Why You Smell Gas Near the Water Heater
A gas water heater has a supply line coming in, a shutoff valve on that line, a flexible connector, and a gas control on the tank. A leak can start at any of those points. The common causes we find are a fitting that has worked loose over the years, a flexible connector that got kinked or bumped when something was stored against the heater, and a worn gas control valve on an older tank.
Earthquakes are another one. A heater that shifts even a few inches can strain the gas connection. That’s part of why California requires water heaters to be strapped, and why any gas smell after a shake deserves the same response: get out, then call.
None of these are things to inspect yourself with the gas on. Finding a gas leak takes a detector or a soap test done by someone trained to do it, and fixing it is licensed work. Your job is to get everyone out and make the call.
When the Smell Is Coming From the Water
There’s a second, much less dangerous source of a rotten egg smell around a water heater: the hot water itself. Here’s the difference.
Gas smells in the air around the heater or in the room, whether or not any water is running. Sulfur in the water shows up at the faucet, and only when you run hot water. Cold water from the same tap smells fine.
If it’s only in the hot water, the cause is usually inside the tank. NDSU Extension explains that a rotten egg smell only from the hot water tap means sulfates in the water are reacting with the magnesium anode rod in the heater, producing hydrogen sulfide gas. It’s the same smell as a gas leak, which is why people mix them up.
LA water does contain sulfate. LADWP’s 2025 drinking water quality report shows average sulfate ranging from 41 mg/L in Los Angeles Aqueduct water to 182 mg/L in water from the Metropolitan Water District’s Diemer plant, depending on where your water comes from.
If you’re not sure which one you’re smelling, treat it as gas. Get out and call SoCalGas. Nobody minds a false alarm, and a gas leak isn’t something to sniff-test.
Fixing a Smelly Hot Water Tank
If the gas company has ruled out a leak and the smell is only in the hot water, it’s a plumbing fix, not an emergency. NDSU recommends removing the anode or replacing it with an aluminum one, and having your water tested before you base treatment on it. A plumber can swap the anode, or put in a powered anode that doesn’t react the same way, and flush the tank.
Don’t pull the anode yourself. It’s often seized in place, and the tank has to be drained and the water and gas handled correctly. If the heater is old, it may be time to think about replacement instead. Our guide to water heater lifespan in LA covers the signs.
After the Gas Company Leaves
If SoCalGas finds a leak at the water heater, they may shut off gas to the appliance or the house and red-tag it until it’s repaired. The repair is on the house side, on your gas line, connector or water heater, and that’s where a licensed plumber comes in.
Hard Hat Rooter and Plumbing repairs gas lines and services and replaces water heaters across Los Angeles County. We answer 24 hours a day with a live person, and quote a flat rate before we start. Once you’re safe and the gas company has been out, call (855) 331-7788.
