Most of us are familiar with the term “hard water.” We are bombarded daily with advertising for products guaranteed to combat the white, crusty residue of hard water on shower heads and coffee pots. But what, exactly, is hard water?
Water, in its natural state, is not “hard.” In fact, the “softness” of rainwater has been common knowledge for centuries. It is only as rainwater seeps through earth’s soil and rock on its way to underground aquifers that it becomes “hardened” by the accumulation of dissolved minerals, primarily calcium and magnesium. The magnitude of hardness is determined by the amount of these minerals per gallon of water and is measured as “grains per gallon” (gpg). From 0.0 - 1.0 gpg (soft) to 10.5 - 50 gpg or more (extremely hard), approximately 85% of American homes are plagued with some degree of hard water. Central Texas, with its calcium-rich limestone aquifers producing a gpg level of 14.0+, boasts some of the hardest water in the country.