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How to Test for the Hardness of Water

By Johnathan Cronk ; Updated July 21, 2017

The most common water problem is hardness, which is caused by calcium. No natural water supply is free of hardness. Hardness is measured in grains per gallon, parts per million or milligrams per liter. If you are testing swimming pool water, most swimming pool stores will test your water for free if you bring in a sample. However, you can test your water for hardness at your home or in your pool using a water hardness test kit.

How to Test for Water Hardness

Purchase a water hardness test kit at your local hardware or swimming pool store. Inside are two vials filled with liquid, one labeled GH (for general hardness) and the other KH (carbonate hardness). There also will be two empty tubes within the kit.

To test your home's water, fill the empty tube with tap water. Fill it only to the “test” line. Put two to three drops of the GH liquid into the water. Allow the drops to settle and view the results. The test tube is designed to show you if the GH level in your water is too high or low.

Take the other empty tube and fill it with tap water. Repeat step two using the KH liquid. Check the results to determine if the KH is too high or low.

Once you have determined whether or not your water is hard, you can decide what action to take if necessary, such as buying a water softener to remove hardness.


About the Author


Johnathan Cronk is a freelance writer and began writing at the age of 18. Throughout his career he has specialized in sports, how-to and advice articles. He has also written sales pitches in the corporate setting since 2001. He studied business at Hudson Valley Community College before transferring to the State University of New York, Albany.