Reverse osmosis is a water purification technology that uses normal household water pressure in order to force water through a membrane that separates and flushes impurities and contaminants from the water. Three to nine gallons of water are needed to produce one gallon of purified water, making it ill-suited to arid and semi-arid environments.

If you have a problem with the taste, smell, or color of your household water, have the water analyzed before you take any steps or make any purchases to remedy it. This will help determine whether water treatment is necessary, and if so, the most appropriate and cost effective means of treating the water. Your problem might be better addressed by using a distiller, a mechanical or carbon filter, or a water softener.

If you insist on installing a reverse osmosis system, expect to pay in the range of $500 to $1,000 for it. More than 90 percent of dissolved solids in water can be removed with a new reverse osmosis unit, but system efficiency drops as the system ages. Care must be taken to prevent precipitate buildup and scaling. If your water is hard, a water softener must be installed or the membrane filter will quickly plug up.