What is calcium bicarbonate?

Calcium bicarbonate is a chemical with the formula C₂H₂CaO₆, and it is one of the major causes of hard water. It is one of the salts of carbonic acid, containing the negative ion HCO₃. Calcium bicarbonate typically exists solely in a water solution.

All water molecules that have contact with the atmosphere absorb some carbon dioxide. Some water, such as the water found in streams, also encounter s rocks and other sediments. The water molecules of this water gain metal ions such as magnesium and calcium, which can react with the carbon dioxide and water. As a result, compounds such as calcium bicarbonate form and create hard water.