Gas Smell Near a Water Heater: What to Do First
Leave first, call from a safe distance, and let the water heater wait. Here is the order that federal pipeline safety guidance sets out.
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What Should You Do If You Smell Gas Near Your Water Heater?
Leave the building on foot immediately, take everyone with you, and call 911 from a safe location, then notify the gas utility. Do not try to find where the smell is coming from, and do not operate anything electrical on the way out.
That order comes from the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA), which tells anyone who suspects a leak to “Leave the area by foot immediately” and not to try to locate the source of the odor. Source: PHMSA, Pipeline Leak Recognition and What to Do, accessed 2026-09-22.
The same response applies whether the smell is next to the water heater, the furnace or anywhere else in the building: treat it as gas, and leave.
What Should You Avoid Doing When You Smell Gas?
Avoid anything that could make a spark: light switches, phones, doorbells, plugs, garage door openers, vehicles and open flames. PHMSA lists each of these in its guidance on what not to do during a suspected leak.
| Do | Avoid |
|---|---|
| Leave the area on foot straight away | Searching for the source of the smell |
| Direct other people to leave, and stay upwind | Using a telephone or cell phone inside |
| Call 911 from a safe location | Operating light switches or pulling plugs from outlets |
| Then notify the gas utility | Ringing doorbells; knock by hand instead |
| Give the operator your name, number, location and a short summary | Opening an automatic garage door or starting a vehicle |
PHMSA also warns against lighting a match or causing any other open flame, and against trying to put out a gas fire. Leave that to the fire department.
PHMSA’s list of what to do begins with turning off gas appliances. Do not go to the water heater to do that. PHMSA also says not to try to locate the source of the odor, and the appliance you suspect is exactly where the smell is; reaching its gas control means approaching the leak and operating a gas component. Leaving comes first. PHMSA states that on notification the utility dispatches trained personnel to isolate the emergency, and that is who shuts the gas off.
Why Does Natural Gas Smell Like Rotten Eggs?
Natural gas has no smell of its own, so an odorant called mercaptan is added to it before distribution to make leaks detectable. The National Institute for Occupational Safety and Health (NIOSH) describes mercaptan as a sulfur-containing compound whose odor is described as smelling like a rotten egg or rotten cabbage.
PHMSA describes the same odorant as giving natural gas a skunk-like odor. Different people describe it differently, which is why any unfamiliar sulfur, egg or skunk smell near a gas appliance is treated as gas. Source: NIOSH, Odor Fade in Natural Gas and Propane, accessed 2026-09-22.
Can There Be a Gas Leak Without a Smell?
Yes. NIOSH warns that the odorant in natural gas and propane can fade, so a leak does not always smell.
NIOSH explains that a lack of odor can result from gas contacting soil, concrete and building materials such as drywall and wood, as well as new piping. It also names medical conditions that reduce or remove the sense of smell. NIOSH’s recommendation to fire departments is not to rely on smell alone to decide whether gas is present.
Smell is also not the only sign. PHMSA lists sound as another: a leak can make anything from a quiet hissing to a loud roar, depending on its size. If you hear hissing near a gas line, respond the same way you would to a smell.
Is It Gas, or Is It the Hot Water That Smells?
A smell in the air around the appliance is treated as gas; a smell that only arrives with the hot water at the tap is a water problem. Where there is any doubt, respond as if it is gas.
Hot water that smells of sulfur when it leaves the faucet, with no odor in the air around the water heater, is a separate issue covered on Rusty, Discolored, or Smelly Hot Water in Harrisburg, PA. That page is for a smell in the water itself. It is not a reason to stay inside if you can smell something in the air near a gas appliance.
What Happens to the Water Heater After a Gas Smell?
Once the gas utility or emergency responders have cleared the building, the water heater and its gas connections are inspected and repaired before the appliance goes back into service. We do not work on a gas appliance until that clearance has been given.
The work that follows depends on what was found: a connection, the gas control, the venting or the appliance itself. Our repair scope for gas units is on Gas Water Heater Repair in Harrisburg, PA. If the unit turns out to be at the end of its life, replacement options are covered on Gas Water Heater Installation in Harrisburg, PA.
We serve Harrisburg City and the surrounding communities, day or night. For other water heater topics, see our water heater guides.
Frequently Asked Questions About a Gas Smell Near a Water Heater
Can I use my phone inside if I smell gas?
No. PHMSA advises against using a telephone or cell phone when a leak is suspected. Leave the building on foot first, then call 911 from a safe location and notify the gas utility.
Should I look for where the gas smell is coming from?
No. PHMSA advises against trying to locate the source of the odor or leak. Leave the area on foot immediately and direct other people to leave too.
What does a natural gas leak smell like?
Natural gas has an odorant called mercaptan added to it. NIOSH describes the odor as smelling like a rotten egg or rotten cabbage, and PHMSA describes it as skunk-like.
Can a gas leak happen without any smell?
Yes. NIOSH warns that the odorant in natural gas can fade, for example when gas contacts soil, concrete, drywall, wood or new piping. A hissing sound near a gas line is another warning sign.
Should I turn off my water heater if I smell gas?
Not by going to it. PHMSA lists turning off gas appliances, but it also says not to try to locate the source of the odor, and a suspect appliance is where the smell is. Leave on foot, call 911 from a safe location, and let the utility isolate the gas.
Who repairs the water heater after a gas smell?
Once the gas utility or emergency responders have cleared the building, a gas appliance technician inspects and repairs the water heater and its connections. Harrisburg Water Heater Pros does this work across Harrisburg City and the surrounding communities.
Once the Building Is Cleared, Call Us
After the gas utility or emergency responders have cleared the building, we repair the appliance and its connections. Call from outside, any hour.
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