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| Equipment to distill water |
Up until World War Two, distilling sea water to fresh water was time consuming and expensive in fuel. The saying was: "It takes one gallon of fuel to make one gallon of fresh water." Shortly before the war, a Dr. R.V. Kleinschmidt developed the compression still, that became known as the Kleinschmidt Still, for extracting fresh water from sea water or contaminated water. By compressing the steam produced by boiling water, 175 gallons of fresh water could be extracted from sea water for every gallon of fuel used. During World War Two this unit became standard on Allied ships and on trailer mounts for armies. This method is still in widespread use for ships and portable water distilling units.
Drinking distilled water
Drinking distilled water is quite common. Many beverage manufacturers use distilled water to ensure a drink's purity and taste. Bottled distilled water is sold as well, and can usually be found in supermarkets or pharmacies. Water purification, such as distillation, is especially important in regions where water resources or tap water is not suitable for ingesting without boiling or chemical treatment.
Municipal water supplies often add or have trace impurities at levels which are regulated to be safe for consumption. Many of these additional impurities, such as volatile organic compounds, fluoride, and certain other chemical compounds are not removed through conventional filtration; however, distillation can eliminate some of these impurities.
Distilled water is also used as drinking water in arid seaside areas which do not have sufficient freshwater, by distilling seawater.
Health concerns
The drinking of distilled water has been both advocated and discouraged for health reasons. The lack of naturally occurring minerals in distilled water has raised some concerns. The Journal of General Internal Medicine published a study on the mineral contents of different waters available in the US. The study concluded
Drinking water sources available to North Americans may contain high levels of Ca2+, Mg2+, and Na+ and may provide clinically important portions of the recommended dietary intake of these minerals. Physicians should encourage patients to check the mineral content of their drinking water, whether tap or bottled, and choose water most appropriate for their needs.
It is often observed that consumption of "hard" water, or water that has some minerals, is associated with beneficial cardiovascular effects. As noted in the American Journal of Epidemiology, consumption of hard drinking water is negatively correlated with atherosclerotic heart disease. Since distilled water is free of minerals, it will not have these potential benefits.
While a growing number of people prefer fluoride-free water for health reasons, others still suggest that—because distilled water lacks fluoride ions that are added by many governments (e.g. municipalities in the United States) at water treatment plants using fluoridation for its inhibition of cavity formation—the drinking of distilled water may increase the risk of tooth decay due to a lack of this element. Of course fluoride can still be applied to the teeth alone with toothpaste and fluoride therapy.