Heart Disease: Soft Water vs. Hard Water
Numerous studies have been published on the relationship between drinking water and cardiovascular mortality. Two beneficial factors continually stand out C hardness and total dissolved solids (TDS). Both are associated with lower mortality from heart disease.
Hardness refers to the amount of calcium and magnesium, or calcium carbonate in the water. The more calcium carbonates the harder the water; lower amounts equal softer the water. TDS is a measurement of all the minerals in the water, not just calcium or magnesium.
One major study, the British Regional Heart Study, analyzed 253 towns. They found 10% to 15% more cardiovascular deaths in soft water areas than in hard water areas. The ideal level of hardness was 170 mg/l.