How a Reverse Osmosis System Works
The scientific principle behind these systems is osmosis, which is the movement of molecules through a semipermeable membrane into an area of lower concentration. In practice, a reverse osmosis system is placed onto the water line entering the house, where it creates two areas of differing pressure with a membrane about the thickness of cellophane between them. The incoming water is at higher pressure, and osmosis forces it through the semipermeable membrane. The membrane only allows water to pass through it, however, and traps impurities on the other side. The impurities are flushed out, and clean water continues through the water pipes.
Contaminants that Reverse Osmosis Systems Remove
The semipermeable membrane can remove more dissolved inorganic solids from water than a standard filter, trapping pollutants down to .001 microns in size. Here are some of the impurities that one these systems will block from entering the rest of your freshwater plumbing: sodium, iron, zinc, cadmium, mercy, arsenic, magnesium, nickel, cyanide, fluoride, nitrate, potassium, phosphate, iron, calcium, and chloride. Many of these impurities will slip right through standard filters, but a reverse osmosis filter can stop them easily.