Water naturally evaporates from oceans, lakes, and rivers to form clouds. Pure water then falls to the earth as rain, snow, and sleet cleaning the air, and picking up contaminants on the way down. This water, which falls back to the earth, becomes more aggressive. As moisture hits the earth and filters through layers of rock and dirt, it picks up minerals like calcium and magnesium which concentrate the hardness of the water.

Hardness can cause a variety of aesthetic challenges for homeowners. Hard water creates a mineral buildup on water-using appliances such as water heaters, dishwashers, and laundry machines. This mineral scale decreases efficiency and causes premature ware on the appliances. In addition, because hard water contains contaminants that interfere with cleaning, homeowners find themselves using more soap and chemicals to clean. To avoid these problems, homeowners often invest in a water softening unit to remove the hardness from the water.