Hard water has small amounts of dissolved calcium, magnesium and other minerals. In geographic regions rich in calcium-based deposits, such as limestone, water acts as a solvent. It dissolves minerals and carries them into rivers and streams. Water hardness is measured in terms of grains per gallon, milligrams per liter (mg/L), or parts per million (ppm). According to the US Geological Survey, nearly 85 percent of the U.S. has hard water. Regions with the hardest water -- the Rocky Mountain region, the mid-west and the Ohio River valley -- generally have rich mineral deposits.
Hard water is not harmful to your health, but hard water mineral deposits can become a homeowner's nightmare. It leaves hair dull and lifeless. Household soaps and detergents lose their cleaning effectiveness. A more serious side effect is the build up a common hard-water deposit, calcium carbonate, in pipes. Over time, calcium-clogged pipes must be replaced. Calcium deposits in the hot water heater affect its efficiency. A water softener installed in your home prevents calcium deposits through an ion-exchange process. While a softener can't remedy existing deposits, it does prevent future hard water deposits.
About Hard Water
How Softeners Work
Non-precipitating water softeners, the type most commonly used in homes, treat hard-water through an ion-exchange process. A water-softener tank filled with negatively charged polystyrene beads, called "zeolite," is installed in the home. Calcium and magnesium ions dissolved in hard water are positively charged. As hard water passes through the softener, positively charged minerals cling to the negatively charged beads. Once beads are saturated with calcium and magnesium, a backwash of brine or salt water, stored in a separate tank, flushes over the beads.Salt is a compound of sodium and chloride ions held together in weak bonds. When flushed through the softener tank, salt water dislodges calcium and magnesium ions from the beads. Calcium and magnesium bond with chloride ions, sodium remains in solution, and the new compounds, calcium chloride and magnesium chloride are washed down the drain.
Hard water is not a health hazard. In fact, drinking hard water is a source of trace calcium and magnesium in our diets. Softened water, however, can be harmful. Patients on low-sodium-intake diets and those with heart or circulatory issues are cautioned not to drink soft water. In fact, many homeowners who install water softeners intentionally bypass the kitchen water supply. Softened water is not recommended for plants, too. Salt is a natural herbicide. Increased soil salinity may kill less hearty plants that don't thrive in saltier soil conditions.
An alternative to a sodium is potassium, which works well in ion-exchange softeners. Potassium chloride is also a type of salt, and when used in place of sodium chloride for the salt-water wash, it reduces sodium levels in drinking water. People sensitive to sodium levels might do well with potassium chloride. However, the Canada Mortgage and Housing Corporation reports that both sodium and potassium-softened water presents health risks. Softened water is not recommended for drinking or cooking.
If you don't want an ion-exchange softener, a precipitating softener conditions hard water with washing soda, which is a sodium salt of carbonic acid, or borax, which is sodium borate. When dissolved in water, these compounds release sodium ions, which displace calcium and magnesium. While precipitating softeners cannot prevent calcium buildup in the hot water heater and incoming water pipes, the addition of borax and washing soda as detergent boosters improve cleaning and prevent hard-water deposits on your laundry. For lifeless hair, an acidic solution of white vinegar, citric acid or lemon juice will strip hard water deposits from your hair.
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