Water Hardness in the United States


Simply defined, water hardness is the total amount of dissolved calcium and magnesium in the water supply. However, it should be known that hard water is not only caused by these two minerals alone, but a variety of dissolved polyvalent metallic ions are involved.

With upwards of 330 million inhabitants as of 2019, it is known that more than 85% of American homes have hard water. But what does this mean for the United States of America?

Let’s take a look at water hardness in the country: the good, the bad and the ugly.

Water Hardness

While we briefly defined water hardness, let’s take a deeper dive to understand the concept.

Hard water, also known as total hardness, occurs when water makes its fascinating journey through different earth’s layers of natural rocks and soil.

First, the water percolates through various deposits of earth, which include chalk, gypsum and limestone. Typically, these are made up of large amounts of calcium and magnesium carbonates, bicarbonates and sulfates, which turns the water hard.

In the United States, hardness over 120 mg per liter of calcium carbonate equivalent is ranked as “hard” or “very hard.” It was found that over half of the water stations in the country have this type of water, while the other half were noted as “soft” or “moderately hard.”

The reason behind the hardness is that the majority of the surface rocks throughout North America are sedimentary. In addition, the mountain region of the west and southwest consist of igneous rocks, while the Appalachian Mountain region of the U.S. and eastern Canada are made of metamorphic rocks.

Limestone, which is a carbonate sedimentary rock commonly found, is often composed of the skeletal fragments of marine organisms such as coral, foraminifera and molluscs. In relation to minerals, it’s heavy with calcite and aragonite, leading to increased water hardness.

The bi-national Great Lakes region, straddling the Canadian border, has some of the hardest water in America. To note, the lakes of this area make up over 20% of freshwater on earth.


One fallout of hard water is the impact that it has in industrial settings, as well as dwellings. 

Critical problems, including malfunctions and costly repairs, are common. This includes instances such as the breakdown of boilers, water towers and other equipment that is used with water that has total hardness. As a result, folks must stay up to date with monitoring.

A way in which concerns can be avoided is by water softening. There are a few ways to do this, but one of the most popular involves the use of ion exchange resins. During this process, ions are replaced by twice the number of monocations, such as sodium or potassium.

It’s important to note that the main difference regarding water softening treatment is timing, where the softening occurs at either the point-of-entry or the point-of use. However, point-of-entry has been banned in some states, such as California, which finds that the process is harmful to the environment and to the health of water consumers.

Impact on Humans

The World Health Organization notes that “there does not appear to be any convincing evidence that water hardness causes adverse health effects in humans.” Additionally, it has been noted that there is moderate health benefits of consuming hard water, due to the inclusion of the dissolved calcium & magnesium, especially for those who do not get enough.

As already noted, the buildup of limescale within industrial settings (and within the home, on faucets, kettles and water heaters) causes a concern for humans. Another problem with hard water involves the lack of foam formation when soap is added to water, as the soap reacts to the calcium to form a “soap scum,” leaving hands covered in an unappealing film.

Due to this reaction, there are also concerns with washing clothes, dishes and other fabrics. As a result, it’s important for those in hard water areas to utilize more soap and detergent in order to get things clean, something that those with soft water do not need to consider.

By Mitte Team — Nov 4, 2019
The information contained in this article is provided for educational and informational purposes only, and should not be construed as health or nutritional advice.

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