Reverse osmosis was developed to remove salt from sea water for military submarines. The reverse osmosis process draws water through a membrane. Salt water is put on one side of the membrane and pressure is applied to stop, and then “reverse,” the osmotic process. It generally takes a lot of pressure and is fairly slow, removing all minerals in the process.
As already mentioned, water without minerals can be a health problem. Dr. Zoltan Rona comments in her book ‘Pure Water’ against the use of de mineralized water produced by distillation and reverse osmosis. Dr. Rona adds,”Longevity is associated with the regular consumption of hard water that is high in minerals. Disease and early death are more likely to be seen with the long term drinking of distilled water.” Again, the water produced by reverse osmosis is similar to the distillation process, purified yet, devoid of healthy minerals. Here’s an example of an RO system that remineralizes water.