Many industrial and domestic water users are concerned about the hardness of their water. Hard water requires more soap and synthetic detergents for home laundry and washing. The harder the water the more calcium buildup that will occur inside metal (mostly steel) pipes, faucet aerators, shower heads, water heaters, dish washers, etc.

The information above coupled with a homeowners water use records is the necessary information for properly sizing water softener for the residence or business.

Removing hardness from water is called softening and hardness is mainly caused by calcium and magnesium salts. These salts are dissolved from geologic deposits through which water travels. The length of time water is in contact with hardness producing material helps determine how much hardness there is in raw water.

The two basic methods of softening public water supplies are chemical precipitation and ion exchange. Other methods can also be used to soften water, such as electrodialysis, distillation, freezing, and reverse osmosis. These processes are complex and expensive and usually used only in unusual circumstances.

Water becomes hard by being in contact with soluble, divalent, metallic cations. The two main cations that cause water hardness are calcium (Ca2+) and magnesium (Mg2+).

• Calcium is dissolved in water as it passes over and through limestone deposits.
• Magnesium is dissolved as water passes over and through dolomite and other magnesium bearing formations.

Because groundwater is in contact with these geologic formations for a longer period of time than surface water, groundwater is usually harder than surface water.

Although strontium, aluminum, barium, iron, manganese, and zinc also cause hardness in water, they are not usually present in large enough concentrations to contribute significantly to total hardness.