Internal Noises in Water Heater (#123)


Occasionally residential water heaters become noisy after a short period of service. These sounds are described as rumbling, bubbling, surging or boiling noises.

Since many water heaters are installed where they are somewhat isolated from living areas, their owners are not aware of the condition. However, where water heaters are located adjacent to sleeping rooms, or other living areas, they may be heard in the quiet of night. These sounds can be annoying.

The noisy condition is a result of lime formations or sediment collecting on the tank bottom. It is not uncommon to find quantities of sand and other minerals settling out of the water and onto the tank bottom.

When the gas burner is on, droplets of water bubble through the crusty formations and sediment, creating the noise problem.

Electric water heaters, with immersed heating elements, frequently develop “singing” or “hissing” sounds. This is caused by lime or scale accumulating on the element blades. Removal and scraping or cleaning with vinegar may help. Severe situations may require element replacement (Follow instructions before removing elements).

Sometimes the owners report that a previous water heater or another water heater in a neighbor’s home is relatively quiet. It is difficult to explain why this should be, unless we know all the conditions. For example, the silent water heater may be fired at a lower gas rate or be heating water at a lower temperature. Many other factors can influence the problem. However, be assured that another glass-lined water heater placed in the same location and, operated under identical conditions, will become noisy.

It is possible to reduce the noise by disconnecting the water heater and flushing the tank. However, it may not be possible to remove all the lime formations from the tank bottom, and when reconnected, it may become noisy again. In hard water areas, the best solution for eliminating the noise problem is to install a water softener, to inhibit scale build up.