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Test Methods for Water Hardness

The traditional method of testing the hardness of water is the soap method, but with advances in science, those most common methods today rely on chemical reactions to relay the hardness of a water specimen. Those methods are the titration method used by most professionals and water hardness tests kits often used by homeowners. Once you test the water, you will then need to interpret the results and determine whether it needs to be softened. While the Environmental Protection Agency (EPA) does not consider hard water a health hazard, hard water can have an objectionable taste. The National Academy of Science states that extremely hard water contributes an important source of calcium and magnesium to the daily diet.

  1. Soap Tells the Story

    • Before the refinement of the EDTA titration method and the development of hard water test kits, most homeowners and professionals alike relied on the soap and water method of determining the degree of hardness in water. Standing the test of time, this method is still reliable and involves filling one glass halfway with tap water and another halfway with distilled water. Put 10 drops of dish soap in each glass, cover the glass, and shake them up. The glass with the distilled water will form an abundance of soap suds. If your tap water does not, you have hard water. The less suds, the harder the water.

    Professionals Rely on Titration

    • If you were to take a visit to a water treatment facility, you might notice a sink that is always running in the test lab. There is a good reason for this -- to insure the water tested is always the water stored in the system as opposed to the water sitting in the pipes. The titration method uses a sodium ethylene, diamine tetra-acetate (EDTA) solution that elicits a chemical reaction from calcium and magnesium in the water. If either mineral is present, the water will turn red; if not, it will turn blue.

    Homeowners Use Water Hardness Test Kits

    • These kits are usually available online in in retail stores that sell swimming pool supplies. These kits include a bottle with a color chart on the outside and several test strips inside. To use the kit, you will need to turn on your facet and let it run for a few minutes, then hold a strip under the running water for a few seconds. Shake the strip once you remove it from under the tap to get rid of excess water, and then compare the color of the strip to the chart on the bottle. The color the strip matches on the chart will indicate the degree of hardness in your water.

    Interpreting Results

    • The U.S. Department of Interior and the Water Quality Association provides a classification system to assess the degree of hardness in water. The system states that soft water is 0 to 1 grains per gallon, while 1 to 3.5 grains per gallon is slightly hard; 3.5 to 7 grains per gallon is moderately hard, while 7 to 10.5 grains per gallon is considered hard. Anything over 10.5 grains per gallon is very hard. Anything reading over 7 grains per gallon will likely have an objectionable taste, and you may want to consider using a water softener or filtration system. Keep in mind, however, softened water is not good for watering plants and gardens due to high sodium content.

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