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What Are The Spooky Sounds Your Water Heater Is Making?

If you hear hissing, banging, clunking or other chilling noises in your house this fall, you can breathe a sigh of relief that they are probably not from ghosts or other haunters. These spooky sounds may be coming from none other than your water heater. Here are some common sounds you may hear and what they mean.

Banging, Knocking, or Popping

The banging, knocking, or popping noises may be coming from within the water heater or from behind the wall. If it is behind the wall, it may be your pipes shifting. If the water is turned off abruptly to heated pipes, it can cause sudden movement. These pipes can cause damage to your wall eventually.

If the banging, knocking, or popping sound is in the tank, it is likely caused by buildup. Calcium, lime, and other minerals collect and form a layer of sediment. When the water heats, this causes movement of the sediment. As the sediment continues to build, it can deteriorate the tank and put it at risk of leaking or bursting. You can remedy the problem by flushing your tank annually. Learn how to do this here or contact a professional if you’re worried about doing it yourself.


A hissing noise may be caused by several problems. It could be due to your water heater’s temperature being too high. If the temperature is too high, a special valve releases the pressure, which causes a hissing noise. The valve may need to be replaced. Make sure you call a professional to do this. Also, some types of leaks and tank fractures can cause hissing noises.

Another cause of a hissing sound is sediment buildup. As described earlier, sediment buildup can cause knocking or popping sounds, but it can also create hissing sounds when water that is trapped between layers of sediment pushes upward.


If you have this problem, the good news is that the fix may be as simple as opening a valve. If the water heater sounds like it is screaming or screeching, it probably has a limited opening. The culprit is often a valve that is partially closed. It may be near an outlet or on the water heater. Have a professional inspect your water line valves for you to see if there are any issues there.


When your water heater makes a sizzling sound, it is important to call a professional immediately. Sizzling sounds are commonly caused by water that leaks onto the water heater’s burner. A small water puddle around the unit is also a telltale sign of a leak. The leak will continue to worsen, which will cause more water loss and excessive energy consumption. A professional should fix the leak or replace the unit.

Tankless Noises

If you have a tankless water heater, it is normal to hear clicking noises at its flow switch automatically turns off and on. However, knocking or banging noises can indicate calcium deposits. If this is the case, you may need to install a system to soften your water. Other noises may be caused by burner issues, dirty fans, or leaks. Contact a professional to diagnose the noise.


Ignoring spooky sounds from your water heater can quickly turn into a horror story–one moment you’re sitting at home, minding your own business when your water heater breaks and you need emergency service. If your water heater bursts and floods the room, it could lead to water damage and eventual mold growth. The best way to prevent extra expenses is to have a professional inspect your water heater as soon as you notice a strange noise. Contact the professional plumbing team at Pure Plumbing if you’re worried about any noises you hear or the state of your water heater!