The risk relationship between hard water and reduced cardiovascular disease is well known, but it's the magnesium portion of the hardness that accounts for most of the beneficial effect. Most Americans consume less than the optimal daily amount of magnesium recommended for good health. Drinking water can be an important contributor, and the uptake of magnesium from drinking water is more efficient than from most dietary components. Even a small (~10 mg/L) consistent lifetime contribution from water can be an important supplement as we age.

Approximately half of the US population has been shown to consume less than the daily requirement of magnesium from foods (USDA & HHS 2015). Drinking water can be a lifetime contributor of supplemental magnesium to one's total daily intake depending on the source water composition and the treatment it has received.


For magnesium, US levels are 330-350 mg/day for adult males, 255-265 mg/day for adult females, and 290-335 mg/day during pregnancy (IOM 2014). Dairy and water are among the most efficient uptake sources. Magnesium is chelated as the central atom in chlorophyll, so it is present in all green plants (Rosanoff 2013). Some 75% of leaf magnesium is involved in protein synthesis, and 15-20% of total magnesium is associated with chlorophyll pigments, acting mainly as a co-factor of a series of