Fact Checked

What Are the Effects of Hard Water on a Water Heater?

Lori Kilchermann
Lori Kilchermann

The effects of hard water on a water heater are numerous, from the production of scale to the premature failure of electric heating elements. The bottom line concerning the effects of hard water on a water heater can usually be seen in a utility bill. Increased cost to heat water is a common side effect of hard water. Another of the byproducts of hard water on a water heater is the production of sediment making its way into the water lines and creating a blockage. This type of blockage is commonly difficult to detect and can lead to a very costly repair bill in order to locate and remove the blockage.

Hard water contains calcium and magnesium, which can be useful to the human body; however, these minerals are very costly and damaging to appliances in the home. One of the most troublesome effects of hard water on a water heater is the buildup of scale. Scale is formed from heating the minerals in the water. Specifically, calcium scale and mineral deposits or sediment are the result of hard water in a water heater. As the scale builds up, it actually works to insulate the water from the heating effects of the water heater.

A water heater.
A water heater.

Scale buildup in a hot water heater can cost the homeowner incredible amounts of money as the heater struggles to heat water on a daily basis. On electric water heaters, the buildup of scale can actually cause the electric heating elements to burn out prematurely, requiring early replacement. This is commonly the result of buildup forming closely around the area of the heating element and creating a kind of heating chamber that overheats the element. This causes the element to burn out, while the other element continues the struggle to heat the water.

In electric water heaters the build-up of scale can cause elements to burn out prematurely.
In electric water heaters the build-up of scale can cause elements to burn out prematurely.

The scale can also make its way out of the water heater and into the water supply lines. This often results in a water blockage somewhere in the waterline. The scale can become packed into the waterline and form a type of concrete water plug, often requiring the aid of a plumber to remedy the problem. The excessive weight of the scale and deposits can also cause the bottom of the water heater to become bulged and even broken or cracked. The scale generated by the hard water on a water heater can also wreak havoc on other appliances, such as washing machines and dishwashers.

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Discussion Comments


@Animandel - Water filters can remove some of the minerals and help your appliances last longer. But, you should be aware that filters and water softeners are not the same. Many people started using water softeners to protect their appliances from hard water. Water softeners add sodium to the water, which is good for your water heater, but not so good for you if you're drinking the water over a long period.


I didn't know that hard water was such a big issue for water heaters. However, there are so many different ways to filter your water. You should be able to easily take out some of the harmful substances before they damage your water heater. I know there are filters you can buy that will filter all of your water before it enters your house and gets into your dishwasher, washing machine and water heater.


I have a friend who bought a hot water heater and then he had to replace it with a new one a couple years later. If you know anything about hot water heaters then you know they should last longer than this. My friend didn't understand what the problem was with the heater, and he just assumed that he had bought a bad heater. This does happen from time to time even with new appliances.

My friend called a plumber. When the plumber got to the house and took the water heater apart he found that all of the lines had clogged up and all but stopped the water from flowing through. The heater was literally burning itself up.

Of course, it was the hard water minerals that were clogging the lines and causing the problems. This is just one of the problems he had because of his hard water. All of his appliances and pipes have paid a heavy price.

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    • A water heater.
      By: scaliger
      A water heater.
    • In electric water heaters the build-up of scale can cause elements to burn out prematurely.
      By: EuToch
      In electric water heaters the build-up of scale can cause elements to burn out prematurely.