If you think carbon monoxide is leaking in your home, do not look for the source. Get everyone outside into fresh air and call 911 from outside. Carbon monoxide has no smell, no color and no taste, and a plumber cannot safely diagnose it while you stay inside.
This guide explains the warning signs, what to do in what order, which household equipment can produce it and how detectors fit in. It is safety information, not a detection service.
Warning signs to take seriously
- Headache, dizziness, nausea or confusion that eases when you leave the house.
- Several people or pets in the home feel unwell at the same time.
- A carbon monoxide detector alarm that sounds.
- Soot, stains or a yellow flame on a gas appliance where there should be a blue one.
- A pilot light that keeps going out.
What to do, in order
- 1
Leave immediately
Take everyone and pets outside. Do not stop to open windows or search for the cause.
- 2
Call 911
Call from outside. Emergency crews can measure carbon monoxide levels and tell you when it is safe to return.
- 3
Do not re-enter
Stay out until responders clear the home.
- 4
Get checked
Anyone with symptoms should be seen by a medical professional.
Common sources in a home
| Source | Why it matters | Who checks it |
|---|---|---|
| Gas furnace or boiler | A cracked heat exchanger or blocked vent can release fumes | Licensed heating contractor |
| Gas water heater | A blocked or loose flue lets exhaust back into the room | Licensed plumber or gas contractor |
| Gas range or oven | Poor burner adjustment or use as a heater | Gas utility or licensed contractor |
| Fireplace and chimney | Blocked flue or creosote | Chimney professional |
| Garage vehicle or generator | Exhaust entering the house | Never run inside an attached garage |
Water heaters and boilers fall to a plumber where flues and venting are concerned, and our boiler repair and water heater repair pages explain what we look at once the home has been cleared.
Detectors and prevention
Install carbon monoxide detectors on every level and near sleeping areas, following the manufacturer's placement instructions. Test them monthly, and replace them on the schedule printed on the unit.
Have gas appliances serviced on a regular basis. Never use a gas oven to heat a room, never run a generator indoors or in an attached garage and keep vents clear of snow, leaves and debris.
Why plumbing equipment is part of the picture
Gas water heaters and boilers burn fuel, and the exhaust must leave through a flue or vent. If that path is blocked, cracked or poorly sloped, exhaust can spill into the room. This is called backdrafting, and it is one of the reasons annual checks of fuel burning equipment matter.
Signs worth a professional look include rust or soot around the draft hood, a scorched area near the top of the unit, water pooling near a flue and a flame that flickers or burns yellow. These do not prove carbon monoxide is present, but they are reasons to have the unit examined.
What a plumber does and does not do
- A plumber inspects venting, burners and connections on the plumbing equipment.
- A plumber can repair or replace a failing water heater or boiler.
- A plumber does not replace a certified detector or an emergency response.
- A heating contractor or chimney professional may be needed for other sources.
Be wary of any company that says it will find carbon monoxide by inspecting the house while you stay inside. Leave first and let responders clear the home.
Building habits that keep a home safer
- Write the date on a new detector and replace it on the maker's schedule.
- Keep a service record for each fuel burning appliance.
- Never block combustion air openings near a furnace or water heater.
- Keep the flue and vent connections visible and free of storage.
- Make sure everyone in the home knows the exit plan.
None of this takes long. Together these habits reduce the chance of a surprise, and they make an emergency call faster and clearer if one ever happens.
Gas leaks are a different emergency
Carbon monoxide has no smell, but natural gas has an added odor that smells like rotten eggs. If you smell it, treat it as a separate emergency. Do not touch light switches or use a phone inside, leave the building and call 911 and your gas utility from outside.
Both situations call for the same first step. Get out, get to fresh air and call for help before anything else.
Teach the household
Make sure everyone, including older children and visitors, knows what the alarm sounds like and what to do. Practise leaving the house together once. A calm plan that everyone remembers matters more than any piece of equipment.
Appliance problems after a CO scare?
Once the home is cleared, call and we will inspect the fuel burning plumbing equipment.
Gas safety in Marlboro homes
In an emergency, call 911. For a suspected gas smell or leak, leave the building and call your gas utility's emergency line from outside as well. If your home has natural gas, check your utility bill for its emergency number and keep it posted by the phone.
Marlboro Township's housing stock includes many homes built from the 1970s through the early 1990s, and some have original furnaces and water heaters. Age alone does not make an appliance unsafe, but a service history helps. Ask your heating and plumbing contractors when each unit was last checked.
Questions homeowners ask
Get everyone outside to fresh air and call 911 from outside. Do not go back in until responders say it is safe.
A plumber is not the first call. Emergency responders measure the air. After the home is cleared, a licensed professional can inspect the fuel burning equipment and venting.
A gas water heater with a blocked, loose or damaged flue can release exhaust into the home. Annual inspection is a good habit.
Place them on every level and outside sleeping areas, and follow the manufacturer's instructions.
Leave the building and call 911 and your gas utility's emergency number from outside. Do not use switches or phones inside.