Distilled water, rain water, and RO water are either devoid of dissolved inorganic salts, or have very little salts. This has adverse health consequences. We explore the use of rock dust in re-mineralizing water.
Water from springs, is usually rich in minerals, people who consumed such water live healthy lives. If we distill water to remove contaminants, or use reverse-osmosis (RO), then beneficial trace minerals are removed. Recent RO units do put back some of the minerals. A Czech study  has found that water low in TDS (e.g. < 100 mg/L) has effect on water and mineral homeostasis. Low-mineral water markedly: 1.) increased diuresis (alm ost by 20%, on average), body water volume, and serum sodium concentrations, 2.) decreased seru m potassium concentration, and 3.) increased the elimination of sodium, potassium, chloride, cal cium and magnesium ions from the body.
Bio-sand filters , which encourage bacterial activity can introduce some trace minerals into drinking water. The amount is not known, tests need to be done to see if the amounts are significant enough to be beneficial.
We can also imitiate natural process, that combines organic acids from composting of organic matter, with rock dust, to dissolve trace minerals into water.