Fixing Water Heater Noise
Pounding, Sizzling and other

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Fixing the water heater noise such as popping, banging, sizzling, rumbling and high pitch sounds. What causes the noisy water heater, troubleshooting tips and how to avoid the problem.

Water heaters are expensive to buy, installation as well. To avoid future failures and costly service, it is recommended to maintain a heater regularly. Many problems can occur, so recognizing the symptoms and get the right instructions for the proper troubleshooting are mandatory if you want to DIY.

The most common problems are “no hot water”, “not enough hot water”, leaking and noise.


Common symptoms of the noisy water heater

All water heaters, either electric or gas-powered, made by Rheem, AO Smith, Bradford White, Kenmore, GE or any other manufacturer, could have problems associated with the noise, such as:

  • Crackling sound

One of the most common reasons for the annoying water heater noise is the sediment buildup.

Sediment is coming from municipal or well water system in the form of a solid material, and in water heaters, it settles at the bottom of the tank or on the elements. Sediments are mineral deposits such as calcium or magnesium that enter the plumbing system as sand, clay or any other type.

In water, as the temperature rises, these minerals separate and accumulate inside the tank as the limescale.

How to fix the water heater noise

Pounding noise

The most common reasons for pounding water heater noise are the mineral buildup at the bottom of the tank and water hammer. Water hammer occurs when water is flowing through the plumbing and stops suddenly. The first signs of this problem are the pounding noise, banging and thumping sounds and vibration coming not from the heating unit but piping. The only fix of the water hammer and pounding noise is to install the water heater arrestor.

Sizzling noise

Sizzling noise coming from a water heater is the result of the condensate leaking on the hot surface of the gas burner surface. The typical residential model will produce approximately one half-gallon of condensate during the hour of operation. Condensate is a regular occurrence of gas heaters as the flue gases are carrying lots of moisture, so when the condensate is dripping on the hot surface, it is normal to hear the sizzling noise.

Electric water heaters are also making the sizzling sound when the heating elements are covered with the limescale, so water, as it is trapped next to the element, will boil water to steam. Condensation usually stops when the heater reaches a temperature of 115 F.

If the sizzling sound happens due to a water leak, unfortunately, the repair is not easy, and it might require purchasing a new unit.

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Popping noise

Popping sound inside the heater is the result of hard water and sediment buildup at the bottom of the tank and unit’s components. The popping noise comes from the water trapped under the mineral deposits. The steam bubbles would develop under the sediments and explode, making such a sound.

The solution is to lower the water hardness and soften the water. Otherwise, if you don't do the recommended treatment (i.e., deliming or adding phosphoric acid) including the regular flushing/maintenance, the high water temperature will bring even more deposits.

Aluminum hydroxide is another reason for the popping noise. If the water supply has relatively high PH and the heater is equipped with the aluminum anode rod, the chemical reaction will result in the creation of aluminum hydroxide (it looks like the green, blue or gray gel) at the bottom of the tank and on the anode rod. Replacing the aluminum with the magnesium rod with flushing and deliming will eliminate or reduce the noise.

Rumbling and crackling noise

Aluminum hydroxide gel in the heater's tank and mineral build-up are the same reasons for rumbling and crackling noise as seen in the previous problem with the popping noise. As the water is making its way thru the sediments, the rumbling sound is what you will hear.

Ticking noise

Ticking water heater noise is the result of the pressure fluctuations in the plumbing system when flushing the toilet or using the water fixtures, or due to expanding and contracting against the framing or lose connections. The fluctuation can also be heard as the clicking or tapping noise. The energy efficient models are equipped with the heat traps so when the ball is rattling in the nipple; it produces this ticking noise also. If the heat traps are the cause of the sound, you can remove them without reducing the efficiency significantly.


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