Water Softeners

What is Hard Water?

Ruining pipes and appliances worldwide

You've been given the dreaded news: your water is hard. OK, so maybe dreaded is a slight exaggeration, but hard water can cause a lot of problems. Unless you have health concerns that can prevent you from drinking soft water, hard water generally isn't the ideal, although there are, of course, downfalls with soft water, too.

So what happened to make your water supply so hard?

When it rains, the water that comes down is soft. As it passes over rocks and through soil, it dissolves minerals and carries them along for the ride. If it flows into a body of water, like a lake, it will evaporate and become naturally softened once again. But when water is drawn from ground sources like wells or rivers, it will retain those dissolved minerals, making it hard.

Just how hard is your water?

As mentioned in the water softener overview, hardness of water is measured in grains per gallon (gpg), milligrams per liter (mg/L), or parts per million (ppm). The grains or parts referred to are actually minerals. More specifically, the most common minerals found in hard water are calcium and magnesium. While they pose no danger to people or vegetation, they can wreak havoc with plumbing and appliances over time.

Based on the level of minerals in your water, it is classified as follows:

Water Classifications

Grains Per Gallon (gpg)

Parts Per Million (ppm) or Milligrams Per Liter (mg/L)


0 - 1

0 - 17.1

slightly hard

1 - 3.5

17.1 - 60

moderately hard

3.5 - 7

60 -120


7 - 10.5

120 - 180

very hard

over 10.5

over 180

What do the minerals do?

Calcium, magnesium and the rest of the hard minerals are well known for the formation of limescale. Scale is not only responsible for ruining household appliances and creating the need for frequent cleaning of water fixtures, it can also lower efficiency and reduce lifespan when it builds up in a water-heating system.

So which is better, hard or soft?

You'll find support on both sides of the fence when it comes to softening water. Weigh the importance of promises about drinkability, water conservation and possible health benefits that come with hard water against the longer appliance life, more efficient heating and use of fewer cleaning supplies and detergents that are promised with soft. Most experts say softeners should only be considered when hardness is above moderate levels.

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