Noisy Water Heater

How to troubleshoot water heater noise like
pounding, rumbling, crackling, popping, ticking, sizzling

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Noisy water heater article is about common problems in residential water heating and how to troubleshoot annoying noise like rumbling, ticking, pounding...

Water heater noise is usually associated with the two main conditions; water hammer and mineral build-up, but there are also other reasons for noisy heater and plumbing.

It is common to experience the annoying noise your water heater makes after a short period of service. Even if your heater is installed in the area away from the living or sleeping room, you might hear a noise in the plumbing that travels with a vibration waves from the heater.

Noise for example can come either from the gas heater due to the droplets on the crusty formations and sediments; or is associated with the hissing sound on electric units and formation of lime scale on the immersed heating elements.

The most common symptoms of water heater noise

  • Pounding noise

  • Ticking

  • Rumbling

  • Crackling

  • Popping

  • Sizzling noise

Pounding Noise

Why my water heater is making pounding noise?

Mineral buildup and water hammer are the main causes of the pounding noise your heater makes.

When water is flowing through the plumbing system and it is stopped suddenly, the high intensity shock wave travels through the pipeline, making vibration in the piping system, followed by the pounding, banging and thumping noise.

Pounding noise is associated with the water hammer occurrence. Details on how to solve the problem with the pounding noise the heater produces, you can find in the article about water hammer.

Pounding noise can occur due to lime formations and sediments at the tank bottom. To eliminate the noise some professionals will recommend installing water softener, or flushing the system occasionally. How to troubleshoot sediment problem and noisy water heater due to the lime scale; it is explained in our article about sediments and lime build-up.

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Aluminum hydroxide gel in tank or plumbing is one of the main causes of the rumbling noise in the heaters, while the mineral buildup can also be a factor. The aluminum hydroxide gel is the result of the chemical reaction between the anode rod and water condition.

These blue, green or gray gel beads tend to accumulate in the heater drain or in faucet aerators.

Solution for this water heater noise problem should be considered if there is a mineral build up and if there is no:

If the the heater is new and has no lime build-up, simply turn the heater off, remove the anode rod and flush the system thoroughly. Bring the anode back and run the heater.

If there is a lime build up, use one of the recommended delimers (phosphoric acid for example or one recommended by the manufacturer) and follow the procedure for flushing the deposits.


Ticking noise is usually caused by fluctuation in pressure in the piping system. If your heater is energy efficient unit, the odds are that it has heat traps installed. Due to temperature change; expansion and contraction of the elements, heat trap ball is rattling in the nipple.

If there is no other way to eliminate this ticking noise, simply remove the heat traps from the heater. There will be only a minor reduction in the energy efficiency, without affecting the safety of heater's operation.

Another reason for ticking sound might be in the plumbing pipes, due to expanding and contracting against a loose strap or wood framing while making a hot water draw. One of the solutions is to track down where the ticking noise is the loudest, secure the pipe or install plastic spacers.

The simplest solution: Turn the temperature on your heater just a few degrees down.

Popping and Crackling

Lime (CaCO3) in the heater is the result of the water hardness, present almost in every home plumbing, more or less. More lime is created as you heat the water more and due to higher usage in the excessive hardness environment.

Popping and crackling noise is one of the symptoms where water is trapped under the lime deposits. Solution for the noisy water heater due to lime build up is simple, flushing the heater with the proper acidic compound (delimer recommended by the manufacturer).

If the flow is also stopped abruptly it can also cause the popping or crackling noise.

Another reason for crackling might be condensation dripping on the burner or any other hot part's surface.


The main reason for sizzling noise in your gas water heater is due to condensation and or leaking problem; when the water drops are dripping down the flame in the burner or hot surface.

Condensation is created when the hot flue gases are in contact with cooler surfaces. Condensation will form inside the vent and the drops of water will hit hot surface every few seconds making the sizzling sound. It can be seen by looking in the combustion chamber where the flame will first grow very bright and then very dim.

Keep in mind that on some usually older units, even half a gallon of water vapor will be produced every hour of operation.

Condensation should stop when the entire heater is heated above 115 F. If the problem is with leaking, locating and repairing or replacing the leaking element or to tighten the loose fittings, is the solution.

A sizzling gas heater can be very normal as the natural gas has a very high moisture content and therefore in products of combustion.

On the heating elements of the electric water heaters, due to lime scale, water trapped next to the element will also make the sizzling noise, boiling the water to steam.


Water heater noise can be reduced by disconnecting the heater and with a regular flushing. This is the most common solution. If the water is too hard, you might want to consider installing a softener, but consider a negative influence on the anode rod.

Use the following article to learn about lime build-up and deliming process.

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