Water “hardness” is caused by the minerals calcium and magnesium in ground and surface water.
If either or both minerals are present in your drinking water in high concentrations, the water is considered “hard”. These minerals come from sedimentary rock such as limestone that dissolves into our water. Therefore, the result of hard water is difficulty making lather or suds for washing and a build-up of minerals on taps and on other fixtures. Water containing low concentrations of calcium or magnesium is called “soft” water.