Call a plumber: hissing, sizzling or a leak

Why this happens

Rheem says a water heater hissing or sizzling can be dangerous, and lists water dripping onto a hot burner on gas models, a leaking heating element gasket on electric models, and condensation reaching heated parts. Rheem says to turn off power or gas, avoid using the heater, and schedule a professional inspection immediately. A. O. Smith says hissing or sizzling near a gas water heater might mean water dripping onto the burner and warrants immediate professional inspection for safety. Bob Vila says the sound can come from water dripping from a valve or connection onto the hot exterior and turning to vapor, and that larger amounts of water need a professional.

What to do right now

1. If you smell gas, or the hissing is near a gas line or the burner, leave the house and call 911 and your gas utility from outside. Do not switch anything on or off.
2. Stay back from the heater. Bob Vila notes parts of a water heater are very hot and can burn skin, so do not touch the tank, pipes or valves.
3. Look from a distance with a flashlight for water on the floor, at the fittings on top, or at the relief valve pipe, the pipe that runs down from the relief valve near the top or side of the tank. Stay out of any standing water. If water or steam is coming out of the relief valve pipe, keep away from the end of the pipe, never cap, plug or block the relief valve or its pipe, and call a licensed plumber right away.
4. If you can do it safely, turn off the power at the breaker (open only the hinged panel door) or the gas at the shutoff valve, then close the cold water valve leading to the heater, as A. O. Smith advises, by hand and never forcing it, and only if you can reach each control without going near any hot water or steam. Only touch the breaker if you are on a dry floor and nothing electrical is wet, because Ready.gov says not to touch electrical equipment if it is wet or if you are standing in water.
5. Do not use the heater until it has been inspected, and do not open its panels.
6. Call a licensed plumber or an authorized water heater service provider. If a leak is the main problem, the water heater leaking page can help you sort where it comes from.

When to stop. Water pooling or spraying, steam, standing water near outlets or the panel, or any gas smell means stop, stay back and call. Smoke, flames, sparks or a burning smell near the heater mean leave the house and call 911 from outside. If you would have to stand in water to reach the breaker, do not touch it; call a plumber and a licensed electrician. A gas smell, or hissing near a gas line or the burner, means leave and call 911 and your gas utility from outside.

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