Reverse Osmosis is a mechanical process that drives a solvent across a semi-permeable membrane transferring it from a higher concentration of solute, to a lower concentration. This process will filter out unwanted molecules and large particles such as contaminants and sediments like chlorine, salt, and dirt from drinking water. In addition to removing contaminants and sediments, reverse osmosis can also remove microorganisms – which you certainly do not want to drink. It gets water clean down to a molecular level, leaving only pure H2O behind.