Why is my water heater making noise?
Water heaters aren’t completely silent. You might sometimes hear the burner turn on, or heating elements activate, or water move through the pipes. But a water heater that suddenly begins popping, rumbling, humming or hissing is often a sign that it needs attention.
Water heater noises can signal sediment buildup, restricted water flow, a loose component or a developing leak. Knowing the difference can help you address a small problem before you lose hot water, or worse, find water pooling on the basement floor.
Here are some of the most common water-heater noises and what they may mean.
Popping or rumbling noises
Popping and rumbling are among the most common water-heater complaints, particularly with traditional tank-style units.
These sounds are often caused by sediment collecting at the bottom of the tank. Minerals and other particles naturally present in the water settle over time and form a layer around the burner or heating element. Water can become trapped beneath that layer, creating popping or rumbling sounds as it heats and pushes through the sediment.
Cincinnati-area homes can be especially susceptible to mineral buildup due to the region’s hard water.
That said, sediment does more than make noise. It can make the water heater work harder to heat the same amount of water, reduce the amount of usable hot water in the tank and place additional stress on the unit. A professional water-heater flush can remove the buildup and improve performance.
Humming or vibrating sounds
A low hum doesn’t mean something is seriously wrong. In fact, electric water heaters can create a humming sound as water moves around the heating elements.
A louder or newer humming noise may indicate that a heating element is loose. Water flowing around the loose component can create vibration inside the tank.
Vibration can also come from pipes or connections touching nearby walls, framing or other surfaces. If the sound is coming from the pipes rather than the tank, the plumbing may need to be adjusted. You’ll need a plumber for this.
Ticking or tapping sounds
Water expands as it heats. That expansion can cause pipes, valves and other plumbing components to make occasional ticking or tapping sounds.
These noises may also occur when pipes rub against framing or straps as their temperature changes. In many cases, light ticking is more annoying than dangerous.
However, increasingly loud tapping deserves a closer look, particularly if it is accompanied by changes in water pressure, leaking or movement in the pipes. A plumber can determine whether the sound is normal expansion or a sign that a valve, pipe connection or other component needs attention.
Hissing or sizzling sounds
With an electric water heater, sediment may cover the lower heating element and create a sizzling sound when the element turns on. A hissing sound can also result from condensation dripping onto a hot burner or other heated surface.
Look around the base and top of the water heater for moisture, corrosion or water trails. Do not touch electrical components or attempt to repair a gas connection.
If you see active leaking or water accumulating around the unit, call a plumber promptly.
Screeching or whistling sounds
A high-pitched screech or whistle often points to restricted water flow. A partially closed valve or another restriction can force water through a smaller opening and create a sharp noise.
Do not force a valve that is stuck or corroded. Older shutoff valves can begin leaking when disturbed and may need to be repaired or replaced.
Whistling can also be related to pressure inside the plumbing system. Because excessive pressure can damage fixtures, valves and appliances, a persistent high-pitched noise should be evaluated.
Banging sounds from nearby pipes
Sometimes the water heater is blamed for a sound that is coming from the plumbing around it.
A sudden bang when a faucet, washing machine or dishwasher shuts off may be water hammer. This happens when moving water stops abruptly and sends a pressure wave through the pipes.
Water hammer can cause pipes to shake or strike nearby framing. Over time, repeated movement can loosen connections and place stress on the plumbing system.
A plumber can identify the source of the noise and recommend the appropriate repair, which may include securing the pipes, correcting water pressure or installing a water-hammer arrestor.
When is a noisy water heater an emergency?
A little ticking or a mild operational hum may not require immediate service. Contact a plumber promptly if the noise is accompanied by:
Water leaking from the tank or plumbing connections
Rust or corrosion around the tank
A gas odor
A burning smell
Sizzling near electrical components
Sudden changes in water pressure
Water that is dangerously hot
A lack of hot water
A pressure-relief valve that is leaking or discharging frequently
Don’t ignore a new water-heater noise
A noisy water heater isn’t always an emergency, but a new or worsening sound should not be ignored. Popping, rumbling, humming, hissing and banging can all provide clues about what is happening inside the unit or the surrounding plumbing.
Allied Reddi-Rooter provides water-heater maintenance, repair and replacement for homeowners throughout Greater Cincinnati, Northern Kentucky, Dayton and communities along the I-75 corridor.
If your water heater is making strange noises, leaking or no longer producing reliable hot water, call Allied Reddi-Rooter at 513-396-5300 or schedule service online.
