Tap water often contains impurities like phosphates, nitrates and heavy metals. Reverse osmosis water is compartively pure and is odorless and colorless. Water purified via reverse osmosis is free of dissolved minerals. It has the special property of being able to actively absorb toxic substances from the body and eliminate them. Reverse osmosis water does not contain fluoride, which is sometimes found in tap water.

Reverse osmosis water is also free from sulfates, arsenic, aluminum, radioactivity, salts, detergents, bacteria and most viruses. It is classified as soft water, since all hardness is removed during the process of reverse osmosis.

Reverse osmosis water is acidic in nature. The removal of alkaline mineral from water produces acidic water. Acidic water can be dangerous to the body system, causing calcium and other essential minerals to be stripped from bones and teeth, in order to neutralize its acidity.

Reverse osmosis water is useful in aquariums that breed fish originating from the Amazon River. The massive amount of rainwater that flows through the Amazon causes the water to contain very few minerals. The tap water in most homes contains too many dissolved minerals, which makes it difficult for fish caught from Amazon River water to survive. Many fish from the Amazon River basin remain healthier and are much more likely to breed in aquariums that use tap water passed through a Reverse Osmosis filter.

Although reverse osmosis does extract several contaminants from drinking water, its removal capabilities are not ideally suited to the challenges of municipally treated water. Municipal water contains such contaminants as chlorine and volatile organic chemicals. Since these contaminants are physically smaller in size than water, the semi-permeable membrane cannot prohibit them from passing through with the water.

In spite of this shortcoming, reverse osmosis water is becoming very popular amongst Americans, because the benefits far outweigh the drawbacks.