RO water purifier (or RO reverse osmosis water purifier / RO water purifier) that is the use of reverse osmosis technology principle of water filtration water purifier. Under a certain pressure, water molecules (H2O) can pass through the RO membrane, while the source water of inorganic salts, heavy metal ions, organic matter, colloids, bacteria, viruses and other impurities can not pass through the RO membrane, so that a part of the water through the RO membrane to separate out the water that does not pass through the solute increase in the formation of concentrated water.