Gas smell near the water heater: what to do

Natural gas and propane are odorless, so suppliers add a chemical that smells like rotten eggs or sulfur. Smelling it near a water heater means gas may be escaping from a fitting, the gas control valve or the supply line.

What to do

1. Get everyone, including pets, out of the house.
2. Do not operate light switches, the water heater, garage doors or anything electrical on the way out.
3. If it is safe and the shutoff is outside at the meter, the utility may tell you how to close it. Do not go back inside to do it.
4. Call the gas utility's emergency number or 911 from outside or a neighbor's home.
5. Wait for the utility or fire department to clear the home.

What a technician checks

• The flexible gas connector and fittings between the shutoff valve and the heater
• The gas control valve on the heater
• The pilot and burner assembly
• Venting, since a blocked flue can send exhaust into the room

Leaks are found with a gas detector or soap solution, never a flame. If the gas control valve is at fault, see our water heater gas valve replacement cost guide.

When a smell is not a leak

A brief odor right after relighting a pilot, or a rotten egg smell only from the hot water taps, is different. The second one usually comes from bacteria reacting with the anode rod, not a gas leak; see our water heater anode rod guide. If you are ever unsure, treat it as a leak and leave.

Protect your home

Install carbon monoxide alarms near sleeping areas and on each level with a gas appliance, and have gas appliances serviced regularly.

Signs of a gas leak besides the smell

• A hissing or whistling sound near the gas line or valve
• A pilot that burns unusually high or yellow
• Headaches, dizziness or nausea in the home, which can also signal carbon monoxide

After the all-clear

Once the utility or a technician has found and fixed the leak, they will relight the pilot and check the heater's operation. Ask them to confirm the venting draws properly. If the leak was in the heater's gas valve on an older tank, it may be time to compare the repair with a new heater.

Prevention

• Never store gasoline, paint thinner or other flammables near a gas water heater.
• Keep the area around the base clear so the burner gets clean air.
• Have gas appliances inspected when you buy a home or after any gas line work.