Rainfresh reverse osmosis system (commonly called RO) removes dissolved minerals from water such as mercury, nitrates, fluoride, sodium, etc. Most bottled waters are made by reverse osmosis technology and by installing Rainfresh RO in your home, you can have the same fresh and great tasting water at the turn of a faucet. As RO water has very low mineral content, it does not leave white scale deposits (if the water supply is hard or brackish) and is therefore also great for steam irons, indoor plants, tea kettles, humidifiers etc. Rainfresh reverse osmosis system features a 4-stage design with a 50 gal. per day membrane. It also features easy-open housings and a cartridge replacement monitor that reminds you every 6 months to replace the filter cartridges (model RO 450M only). Often consumers regard reverse osmosis as the best drinking water technology for home. While RO does remove a wide range of contaminants, it does not remove most pesticides, VOC and other chemicals and bacteria or viruses.