Whereas some electric water heaters work silently for a long time, It is not uncommon that a new electric heater or one that has been in operation for several months or longer to start making some sounds or noise.
These noises can be concerning as they can be a sign of a problem that is about to happen. Not all sounds should alarm you though.
So in this port, I will address whether heaters should make sounds or remain silent during operation, possible reasons why an electric heater may make some sounds, and what you can do to prevent or fix the concerning noises.
Is It Normal for An Electric Heater to Make Noise?
An electric water heater in operation normally is silent. You may hear some noises when it is heating water or in use.
These noises you hear are not necessarily a sign of the fault with the heater but may be caused by several factors including but not limited to excessive water pressures, expansion of hot-water, airlocks, possibly an issue with the heater itself, and others.
The trick is in determining which of the noises you hear should be of concern or not and what you may be able to do.
You can check the list below as a guide to specific causes of noise in heaters, where you should be concerned, and how you may be able to fix the noise problem.
Is an Electric Heater Supposed to Make Noise?
No, an electric heater is not supposed to make noise – in fact, they can be quiet in their operation with possibly an occasionally gurgling or hissing sound as the water begins to boil, noticeable when you are very close to the heater.
What Type of Noises a Water Heater Can Make?
With an electric water heater installation, you may hear several noises during operation – when heating water or not ranging from the occasional gurgle, hissing, popping, rambling, or rattling noises.
These noises can start suddenly, be occasional, or one-off, and never repeat. In some cases, these noises can progressively become louder with time.
So in general, the frequency and intensity of the noises can vary.
You may also be interested in: What causes electric water heater explosions?
The Different Noises a Water Heater Makes and Causes
While some water heaters are silent in operation, you may experience some noises with some. Some of the common noises experienced with heaters are described below and the possible causes.
- rumbling or buzzing or humming sound. As the water is heated, you may hear some rumbling sounds within the tank. This can happen with both newer and older heaters but usually with the older ones.
One common cause of this is the build-up of sediment within the heater over time, more so depending on the quality of water use.
Over time, the sediment can harden and float around the tank as the water boils making the rumbling sounds, or other times, they sound like knocks in the tank.
Possible solution This is an issue that requires immediate attention. To fix this, periodically flush the water heater to remove any sediment that may have built up.
Check your heater manual for guidance on which connections you may have to remove to properly flush the heater.
- banging sound or water hammer. In some cases, you may hear what sounds like banging or shaking of the pipes and heater system.
This can happen when water flow is suddenly interrupted for example when valves or closed quickly, an issue with automatic water systems.
Possible solution: There are water hammer arresting devices, consider installing them if this is an issue.
Water risers, usually Tee like connections installed in the water system can minimize the problem.
Consult a qualified plumber for help with
- Loud hissing sound or whistling sound when heating water. You may experience loud hissing sounds as water is heated. One likely cause is high water pressure into the tank or an electric element with mineral buildup.
Possible solution: Depending on the magnitude of the water supply pressure, you may need to install a pressure reduction valve, pressure regulator, or surge tank on the water inlet line to reduce the excess pressure.
If the heater element is covered with buildup, it should be cleaned.
Consult a qualified plumbing service for help with this.
- Popping sound. There are two scenarios – the pressure relief valve may produce a popping sound as it releases excess pressure. If the popping is from the pressure relief valve, it is important to get it fixed right away.
The popping sound can be a result of water breaking through the sediment and mixing with the cooler water above the sediment.
Possible solution: You can drain the water heater tank (see heater user manual) and stir the bottom to loosen any sediment that may have built up in the tank.
- Rattling noise. You may experience a rattling noise when the water is flowing. This can be caused by heat traps that prevent heated water from escaping and preventing unwanted loss of hot water.
| No. | Noise | Possible Cause | Fix |
| 1 | rumbling or buzzing or humming sound. | Sediment build up in the heater | Periodically drain and flush tank to remove sediment |
| 2 | Banging sounds or water heater | Usually, automatic valves close quickly | Use water hammer arresting devices or water risers |
| 3 | Loud hissing sound or whistling sound when heating water | Sediment or mineral buildup around the heater element | Periodically drain and flush tank to remove the sediment |
| 4 | Popping sounds in the heater | Combination of sediment buildup and hot water popping through and mixing with the cool water above the sediment | Drain the tank and stir to remove any particles |
Final Word
Electric water heaters can work silently though you can occasionally hear some noises when near the heater.
This does not necessarily mean there is a problem with the heater.
Examples of noises you may hear range from the occasional gurgle, hissing, popping, rambling, or rattling noises.
There are several possible causes including the buildup of sediment in the heater, excess water pressures, closing the valves too quickly including a faulty heater.
Related Topics
