Dissolved calcium and magnesium salts are primarily responsible for hard water. However, hardness can also occur when the divalent cations of dissolved metals, such as: aluminum, barium, iron, manganese, strontium and zinc, combine with anions in the water supply to form salts.
There are two types of hardness compounds that may be present in water: carbonate and non-carbonate. Carbonate hardness can be removed by boiling the water; however, non-carbonate hardness requires the use of softening or filtration to be removed from water. Culligan's premium bottled water is filtered to remove any hard water compounds and is put through a stringent bottled water treatment process, which ensures the water is free of 98% of all dissolved salts and organic contaminants.
The EPA (Environmental Protection Agency) does not regulate water hardness levels. While hard water can make cleaning more difficult, leave behind scale and precipitate soap scum; according to the World Health Organization, there is no convincing evidence that drinking hard water poses any adverse health effects1. After filtering our premium bottled water via reverse osmosis, Culligan adds essential minerals back into the water to enhance flavor.
The hardness level of water is commonly calculated by measuring the amount (milligrams) of hard water compounds per liter of water (mg/L). Water is generally considered hard if it contains more than 120 mg/L of hard water minerals. Municipal tap water can contain high levels of hardness, and homeowners often make the choice to have their water softened and the minerals removed.
1World Health Organization: Hardness in Drinking-Water, 2003: http://www.who.int/water_sanitation_health/dwq/chemicals/en/hardness.pdf