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Distilled water is water that has had virtually all of its impurities as well as electrolytes removed through distillation (that is, boiling the water and re-condensing the steam into a clean container, thus leaving contaminants behind). It is widely used in chemical and biological laboratories.
Purported benefits Many people drink distilled water for its purity and for its improved taste. Municipal water supplies may have trace contaminants at levels which are scientifically believed to be safe, but some people feel safer drinking distilled water. It also has no minerals, which may make it taste better. The drinking of distilled water has been both advocated and discouraged for health reasons. The purported effect of drinking water in its pure form is a 'more powerful solvent' that helps cleanse toxins from the body. Detractors argue that it robs the body of essential minerals in this way and also deprives it of minerals normally acquired from drinking water. While there is no evidence to suggest that drinking distilled water is harmful or leaches minerals from the body, the World Health Organization has assembled considerable research which shows a relationship between drinking water containing naturally-occurring minerals and lower rates of certain diseases. Many people use distilled water in their irons for pressing clothes to reduce mineral build-up and make the iron last longer. However, many iron manufacturers say that distilled water is no longer necessary in their irons. Some people use distilled water for household aquariums because it lacks the chemicals found in tap water supplies. It is important to supplement distilled water when using it for fishkeeping; it is too pure to sustain proper chemistry to support an aquarium ecosystem. Despite the perceived benefits, the cost of distilling water (about 0.04 to 0.10 Euro or USD per liter in 2005) prohibits its use by most households worldwide. Distilled water vs. government-treated water It has been suggested that because distilled water (like reverse osmosis produced water) lacks fluoride ions that are added by many governments (such as most municipalities in the United States) at a water treatment plant for its effect on the inhibition of cavity formation, the drinking of distilled water may conceivably increase the risk of tooth decay due to a lack of this element.* Regardless, most people continue to cook with tap water as treated and delivered by their government, and in cases of fluoridized water this is thought to potentially provide sufficient fluoride to maintain normal prophylaxis in many cases. Studies funded by the World Health Organization and others seem to show a clear relationship between minerals in tap water such as calcium and magnesium and a decreased rate in certain diseases. In many other developing countries, government water treatment is necessary for health, but distilled water, if affordable, can be even safer by eliminating risks caused by variations from standards. An argument against shunning distilled water for displacing government-treated water is that governments treat water because it is much more economical than individual households treating it. Therefore, people who can afford it may choose distilled water for their drinking, and that does not deprive them of an overall health and caries plan, nor does it deprive governments of making changes informed by new knowledge (such as providing a caries prevention plan that includes distilled drinking water). Myths about distilled water A popular myth about distilled water is that it has the dangerous property of being more easily heated above its boiling point without showing the normal characteristics of boiling. This is called superheating. When the superheated water is disturbed or has impurities added to it, a sudden, explosive boil occurs, possibly causing serious injury to anyone near it. In fact, superheating of plain tap water, for instance in the microwave, is just as great a danger as when heating distilled water. In the popular Discovery Channel show Mythbusters, an experiment was conducted where distilled water was placed in a microwave oven for several minutes long enough to boil, but no convection (boiling bubbles) took place. When a contaminant (a sugar cube) was added to the superheated water, it had an explosive effect. However, this effect also occurs with normal tap water, as macroscopic impurities (especially those which carry air bubbles) are needed for boiling to start. The dissolved impurities in tap water are not enough to inhibit the superheating. Unproven cleanliness of bottled distilled water A second criticism of distilled water supplies as used around the world (in 2006) is that individual bottling is often used for economic distribution. Some distributors sanitize and seal the bottle with each filling; however, many households and companies (who keep water dispensers for employees and customers to drink) re-use their bottles. While municipalities and government-organized water services treat and measure contaminants in water, bottled distilled water, while assumed to be contaminant-free (as with piped government supplies where the pipes are not tested), is not necessarily proven to be as safe as assumed, or--at least--safer. For example, even though instructions like the ones below are often given by bottled distilled water suppliers, few standards are available for knowing the effect of using a bottle a long time between washings, for knowing how many people follow the instructions correctly, what happens when they do not follow them at all, or for knowing that the washing is not leaving soap or bleach, or that cracks in the bottle are not harboring bacteria. Although this risk is small enough to be thought negligible, studies are needed to prove it and measure the effect in individual households, and to compare this supply with government-delivered water supplies. Instructions for keeping water bottles and dispensers clean, as given to public consumers: See also | ||||||||
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