A troubleshooting guide about the noisy water heater helps you explore the most common sound problems in residential water heating and learn how to fix bothersome loud noises like rumbling, ticking, pounding, hissing, clicking, knocking...
The water heater noise is usually associated with the two main conditions; water hammer and mineral buildup (sediments), but there are also other reasons for a noisy heater and strange sounds in plumbing.
It is common to experience irritating noises that your water heater makes after a short period of service. Even if your heater is installed in the area away from the living room or bedroom, you might hear a noise in the plumbing that travels with a vibration wave from the heater. Some users complained that the noise appears only at night, some saying in the morning, right after the unit was turned ON or after the shower.
The noise, for example, can come either from the gas heater due to the droplets on the crusty formations and sediments; or electric units associated with the hissing sound and formation of limescale on the immersed heating elements.
Why my water heater is making a pounding noise?
Mineral buildup and water hammer are the leading causes of the pounding noise your heater makes.
When water is flowing through the plumbing system and stopped suddenly, the high-intensity shock wave travels through the pipeline, making vibration in the piping system, followed by pounding, banging, and thumping noise.
The pounding noise, including the knocking sound, is associated with the water hammer occurrence. You can find details on how to solve the problem with the pounding/knocking noise the system produces in the article about fixing water hammer. A solution is to install the water hammer arrestor.
The pounding noise can occur due to lime formations and sediments at the bottom of the tank. To eliminate the noise, some professionals recommend installing a water softener or flushing the system occasionally. How to troubleshoot the sediment problem and noisy water heater due to the limescale; check out the article about sediments and lime build-up.
Aluminum hydroxide gel in tank or plumbing is one of the leading 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 faucet aerators.
A solution for the noisy water heater is as follows:
If 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 buildup, use one of the recommended delimers (phosphoric acid, for example, or one recommended by the manufacturer) and follow the procedure for flushing the deposits.
The ticking noise is usually caused by fluctuation in pressure in the piping system. If your heater is an energy-efficient unit, the odds are that it has heat traps installed. Due to temperature change, expansion, and contraction of the elements, the heat trap ball rattles 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 energy efficiency without affecting the safety of the 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 for this sound 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.
Lime (CaCO3) present in the heater results from the water hardness found in almost every home plumbing, more or less. More limescale is created as the water is heated longer and due to higher usage in the excessive hardness environment.
Popping and crackling noise are the symptoms of water trapped under the lime deposits. A solution for the noisy water heater due to lime buildup is simple, flushing the heater with the proper acidic compound (delimer recommended by the manufacturer).
If the flow is stopped abruptly, it will cause a 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 sound in your gas water heater is condensation or leaking problem; when the water drops are dripping down the flame, on 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 the hot surface every few seconds, making the sizzling sound. It can be noticed by looking in the combustion chamber, where the flame will first grow very bright and then very dim.
Keep in mind that even half a gallon of water vapor can be produced every hour of operation on some older units.
Condensation should stop when the entire heater is heated above 115 F. If the problem is leaking, the solution is to locate and repair or replace the leaking element or tighten the loose fittings.
A sizzling gas heater can be very normal as the natural gas has very high moisture content and, therefore, in products of combustion.
On the heating elements of the electric water heaters, due to limescale, water trapped next to the element will also make the sizzling noise, boiling the water to steam.
The hissing sound is mainly found on electric water heaters, with the corroded heating elements, when water gets in contact with the electrically hot part of the element.
The same sound is heard when the heating element is ON, and water trapped under the scale, formed on the elements, turns into steam. This is also an indication that your water heater needs flushing as the efficiency drops.
Also, water heaters can make a hissing noise when the air is escaping through the TPR valve. By decreasing the temperature, the sound can be eliminated. If the noise and leaking come together, you might want to consider replacing the TPR valve.
The water heater noise can be reduced by disconnecting the heater and with regular flushing. This is the most common solution. If the water is too hard, you might want to consider installing a water softener but consider the negative influence of softer water on the anode rod.
Use the following article to learn about the lime build-up and deliming process.
The noisy water heater is not dangerous but is a good indication that either you have missed regular maintenance, and the unit needs one, or one of the mentioned elements is failing and needs replacement.
If the unit service is hard or you don't know how to do it, check out this company, they will provide you with three free estimates, so you can choose either to make a service call or DIY.