I Smell Natural Gas Near My Furnace or Water Heater What Should I Do Right Now: Leave First, Then Call (Toronto)
If you smell rotten eggs near your furnace or water heater, leave the home immediately without switching anything on or off and call Enbridge Gas at 1-866-763-5427 from outside; if the smell is strong or you hear hissing, call 911 as well. Natural gas is odorless until mercaptan is added, and that additive creates the rotten egg smell that signals a possible leak.
For homeowners, property managers, and residents in the Toronto area, this is urgent safety guidance first: avoid lights, appliances, phones, or anything else that could ignite the gas, get everyone out, and wait for the all-clear from the utility or emergency responders. Once the property is safe, call us and we will connect you with a licensed plumber from our network to inspect the furnace or water heater line, explain what happens after the emergency call, and handle the certified gas leak repair process. Acting fast matters because a gas leak near fuel-burning equipment can lead to fire, explosion, or carbon monoxide danger, so this guide focuses on the immediate safety steps, when to contact Enbridge or 911, what happens next, and how licensed repair is completed.
What to do, in order
Get everyone out
Take people and pets outside and leave the home immediately without stopping to investigate where the smell is coming from, moving a safe distance from the building. Once outside, wait in a safe location, and leave the door open behind you if you can do so on the way out.
Do not touch switches, phones or appliances inside
A light switch, a doorbell, a garage door opener or a phone can spark, so avoid all ignition sources inside the home, including open flames and light switches, because even a small spark can ignite gas. Do not start a car in an attached garage. Make your calls from outside.
Call Enbridge Gas from outside: 1-866-763-5427
The gas utility's emergency line, Enbridge Gas, the gas company, is answered around the clock and the call is free. They will send a technician when a leak occurs to find the source and stop the gas flow. If the smell is strong, or you hear gas escaping or a hissing sound, call 911 and contact emergency services or the local fire department as well. Call for help only from outside the building.
Stay out until you are told it is safe
Do not go back in to open windows or try to reach the gas shutoff valve or gas supply yourself. The utility's technician does that, checks the appliances, and tells you when the house is clear. Once they say it is safe to re-enter or ventilate, fresh air can help disperse any remaining gas.
Then call us for the repair
Once the property is safe, the source still has to be fixed: a water heater gas valve, a connector, gas connections, or a section of gas line. Our assistant confirms what the utility found and your postal code and connects you live to a plumber and licensed technician from our network whose team holds the TSSA gas certificate that work requires.
Call a professional immediately if…
- You smell gas at all. This whole page is the 'call immediately' case; treat any gas odor as a possible real leak, and call the gas utility first, not a plumber.
- A gas appliance has been shut off by the utility and tagged, and needs a repair before it can be relit.
- The pilot light on a gas water heater keeps going out and there is any smell of gas around it.
- A carbon monoxide alarm has sounded. Leave, call 911, and have the gas appliances checked before using them again; carbon monoxide detectors and co alarms matter because incomplete combustion can create carbon monoxide without a smell, and physical symptoms such as headache or dizziness are also warning signs.
What happens once you call
The utility stops the leak and makes the property safe; it does not repair your appliances. That is the plumber's job. Anything on the gas side of a water heater or a gas line, from the shutoff valve to the burner to the vent, must be done by a technician holding a TSSA gas certificate, and every contractor in our network agrees in writing to hold the licences the province requires. Ask for the number.
Once the repair is done, the technician relights and tests the appliance and checks for leaks with a detector, not a match; they may also use soapy water at connections as one safe way to confirm a leak. If the water heater was the source and it is old, expect an honest conversation about replacing it rather than repairing it. After repairs, book annual maintenance and safety checks for the furnace, water heater, and the rest of the heating system.
Questions
What does a natural gas leak smell like?
Rotten eggs or sulphur. In its natural state, natural gas has no smell of its own, so the utility adds an odour that people recognize as a rotten egg smell. A brief faint odor near a stove when a burner is lit can be normal for a second, but persistent gas leak signs near the water heater or gas furnace are not. Dust burning in a furnace at first startup can also create a short-lived odour that should fade quickly, but tiny leaks can cause a faint sulphur smell that keeps coming back.
Should I turn off the gas at the meter?
Only if you already know how, the meter or gas meter valve is outside, and you can shut off the gas at the main gas supply safely on the way out without going back inside. Otherwise leave it to the utility's technician. The important things are to get out, make no sparks, avoid anything that could cause a small spark, and call Enbridge from outside.
Who fixes the leak after Enbridge has been?
The utility stops the gas and makes the property safe, and may tag the appliance as unsafe to use. As part of gas safety follow-up, the contractor should also check burner flames after the repair, since a steady blue flame usually indicates proper combustion and can help spot appliance issues. The repair itself is done by a contractor with a TSSA gas certificate. Call us once the house is cleared and our assistant connects you live to a plumber whose team holds that certificate.
Is a gas smell from the water heater common?
A gas odor or unpleasant smell from the water heater is not common and should not be ignored. Some non-gas sources, including garbage disposals, can also create a rotten egg smell, but a persistent odor around the water heater should still be treated as a gas issue first. A pilot that has gone out lets a small amount of gas escape before the safety valve closes; a failing gas valve or a loose connector can leak steadily, and the same safety logic applies if your home uses propane and you notice a propane smell or smell near gas fireplaces. Do not try a dish soap check indoors, and if outdoor vegetation nearby is wilting or showing yellow patches because leaking gas can affect roots absorbing oxygen, mention that when you call. Either way the response is the same: leave, call Enbridge, then have it repaired by someone certified, since a persistent odor around natural gas appliances can point to an appliance problem rather than a harmless startup smell.