Why Is My Water Heater Making Noise?

Water heaters are not completely silent appliances, but certain sounds can indicate a problem. Here is what different noises typically mean.

Common Water Heater Sounds

Popping or Rumbling

This is the most common noise and usually means sediment has built up at the bottom of your tank. As the heating element heats water trapped under the sediment, it creates these sounds.

What to do: Schedule a tank flush. If your water heater has not been flushed in over a year, sediment buildup is likely the cause.

Sizzling or Hissing

This typically happens when water drips onto hot components, often indicating a leak somewhere in the system.

What to do: Check for visible leaks around the tank. If you find one, call a plumber right away.

Screeching or Whistling

Usually caused by a partially closed valve restricting water flow. This could be the inlet valve or temperature/pressure relief valve.

What to do: Check that all valves are fully open. If the sound continues, have a plumber inspect the valves.

Knocking or Hammering

This is often water hammer, caused by sudden changes in water pressure when valves close quickly.

What to do: This is usually a plumbing system issue rather than a water heater problem. A plumber can install a water hammer arrestor.

When to Call a Plumber

Call immediately if you notice: - Loud banging that shakes the unit - Any sound combined with visible leaks - Sounds accompanied by rusty or discolored water - The unit is over 10 years old and making new noises

Prevention Tips

• Flush your water heater annually to prevent sediment buildup
• Check the anode rod every 3-5 years
• Set temperature to 120°F to reduce mineral buildup
• Have a professional inspect the unit every 2-3 years

Regular maintenance prevents most noise issues and extends the life of your water heater. If you are hearing unusual sounds, do not ignore them. Small problems become expensive repairs when left unaddressed.