Temporary hardness of water is due to the presence of bicarbonates of calcium and magnesium in water i.e., Ca(HCO3)2 and Mg(HCO3) in water. Permanent hardness of water is due to the presence of soluble chlorides and suiphates of calcium and magnesium.
For example, CaCl2 , CaSO4 , MgCl2 and MgSO4 .