Reverse Osmosis units use large amounts of water. These units are expensive to purchase. Usually they are connected to a cooking and drinking line only and installed under the kitchen sink. Regular testing of the water supply is necessary to make sure the membrane is intact. Minerals, bacteria and other substances are left behind when the steam recondenses into relatively pure water.
Distillers remove bacteria, minerals, trace amounts of metals, many organic chemicals and nitrate.
A fractional distiller avoids this problem. Distillers also remove benefi- cial minerals and make water taste flat or bland. Approximately five gallons of tap water is required to produce one gallon of distilled water. Stills are relatively expensive. They require frequent cleaning and may be difficult to keep clean.