Why Is My Water Heater Making Noise?

When your water heater starts making noises, you may wonder if it is about to stop working and leave your family without hot water. Although not all noises mean that it is time to replace your water heater, it is important to try to identify the source of the sound so you can determine if it is time to call a plumber.

Common Sounds Your Water Heater Might Make

Here is a look at some of the most common sounds that your water heater might be making as well as the water heater problems that are typically associated with them.

Knocking Or Hammering

If you can hear a knocking sound within your walls, this is the sound of your pipes heating internally and is referred to as water hammering. When water is abruptly turned off as it is entering or leaving your tank, this may cause the pipes to move and bang against the inside of your walls or studs.

Although this noise is not usually dangerous to a water heater, it could cause wall damage over time if it is not addressed. A water hammer arrestor can be installed between the device and the water heater to keep the problem under control.


If your water heater is making a hissing noise, it could indicate a leak. Look for water or steam coming out of the water heater or one of the pipes leading to it. Any time there is a leak, it is important for a plumber to repair or replace it, so be sure to call for help immediately.

Rumbling, Popping Or Crackling

If you hear these types of noises, it is likely related to the sediments that collect around the element tubes inside your water heater. When the element tubes are off, caked sediments will trap water under them.

Then, when the water heats back up, it makes a popping or cracking sound as it is forced through these deposits. Sometimes it will break off the sediment and cause it to become loose within the tank, and these broken chunks of sediment moving round inside the tank can cause a rumbling noise.

It is particularly common on older units, and the noise usually becomes louder as the deposit layer thickens. These types of noises can often be corrected by cleaning or replacing the element.

If the water heater is not too old, it may be possible to flush the sediment out of the tank and flush and drain the water heater itself. This is important because having too much sediment in the water heater can reduce its efficiency.

If the tank is flushed and the noises continue, the next course of action is checking the thermostat. The noises could be caused by the expansion and contraction of the tank that comes from high heat settings. In these cases, reducing the thermostat to 120 degrees or lower may make the noise stop.

Tapping Or Ticking

Many types of water heaters contain check valves or heat traps in the pipes at the top of the heater that stop water from flowing in the wrong direction inside the pipes. The traps can sometimes make a light tapping or ticking sound. Although this is normal, a plumber can address it if you find it disconcerting.


Electric water heaters typically contain an element that is placed vertically related to the tank, and water that flows around the element may create vibrations that lead to a humming noise. A plumber can tighten the element to help keep this noise at bay.


If you hear screeching sounds coming from your water heater, it is likely caused by water that is being forced through a valve that is not fully opened. This valve may be sitting at the water heater itself or at an outlet such as a sink.

You may be able to determine which valve is the problem by listening carefully to where the noise is coming from. It is advisable to have a professional plumber tighten problematic valves due to the high risk of injury from steam burns.

Noises From Tankless Water Heaters

The noises that come from tankless water heaters are a bit different from traditional water heaters. A clicking noise is usually the flow switch turning itself on and off in order to control the flow of water.

This is considered completely normal. However, if it makes a lot of noise when it is turned on, there could be calcium deposits left behind because of hard water. A water softener system can be installed to help address the hard water.

Another reason a tankless water heater may make noise is an issue with its burner. There could also be a leak in the sealed combustion or a dirty fan.

Reach Out To Baumbach Plumbing & Remodeling

If your water heater is making noises or not performing optimally, you need professional plumbers to identify the problem and determine the best solution.

Baumbach Plumbing & Remodeling can handle all of your Northern Virginia residential plumbing needs, so get in touch today to find out more about our affordable services.

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