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What is Water Hardness?

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the effects of water hardness on your body and home

Hard water is water that has high mineral content. It is formed when water filters through deposits of limestone, chalk, or gypsum which are largely made up of calcium and magnesium carbonates, bicarbonates, and sulfates.

Hard water is high in dissolved minerals, largely calcium and magnesium. The level of hardness is determined by the amount of these dissolved minerals that can be detected. In hard water, soap reacts with the calcium to form "soap scum."

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Hardness can be found in both types of water, municipal and well. It can range from slightly hard to extremely hard water.

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Measuring Hardness

Measuring Hardness

The grain per gallon (GPG) is a unit of water hardness defined as 1 grain (64.8 milligrams) of calcium carbonate dissolved in 1 US gallon of water (3.79 L). This is 1 part in about 58,000 parts of water or 17.1 parts per million (ppm).

For a good comparison of the relative weight and size of a grain, one standard aspirin tablet usually weighs 5 grains. You can download this chart for your reference.

Water Hardness Description Grains  Per Gallon (GPG) Parts Per Million (PPM)
Soft Water Less than 1.0 Less than 17.1
Slightly Hard 1.0 to 3.5 17.1 to 60.0
Moderately Hard 3.5 to 7.0 60.0 to 120.0
Hard Water 7.0 to 10.5 120.0 to 180.0
Very Hard 10.5 and over 180.0 and over

Effects of hard water

Hard water can have a negative effect on our home goods, cleansers, and body. 

Limiting Cleaning Power 

Hard water reacts negatively to soaps and detergents. Instead of creating a rich and foamy lather, it forms a substance that is curdy. More soap and detergent are necessary to overcome the negative effects of hard water.

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