Drinking water has been distilled from sea water since at least ca. 200 AD when the process was clearly described by Alexander of Aphrodisias. Its history predates this, as a passage in Aristotle's Meteorologica (II.3, 358b16) refers to the distillation of water. Captain Israel Williams of the Friendship (1797) improvised a way to distill water, which he described in his journal.
In chemical and biological laboratories, as well as industry, cheaper alternatives such as deionized water are preferred over distilled water. However, if these alternatives are not sufficiently pure, distilled water is used. Where exceptionally high purity water is required, double distilled water is used.
Distilled water is also commonly used to top off lead acid batteries used in cars and trucks. The presence of other ions commonly found in tap water will cause a drastic reduction in an automobile's battery lifespan.
Distilled water is preferable to tap water for use in automotive cooling systems. The minerals and ions typically found in tap water can be corrosive to internal engine components, and can cause a more rapid depletion of the anti-corrosion additives found in most antifreeze formulations.
Distilled water is also preferable to tap water for use in model steam engine boilers and model engines of other types. Mineral build-up resulting from the use of tap water in model boilers can severely reduce the efficiency of the boilers if run for long periods. This build-up is known as boiler scale.
Use in Steam Irons: Although possibly once the recommended procedure, using distilled water in steam irons for pressing clothes (once thought to help reduce mineral build-up and increase iron life ), now most manufacturers say that distilled water is not only no longer necessary in their irons, but can actually result in malfunction, including spitting and leaking during use. This may occur due to the lack of impurities in distilled water, which can heat beyond the normal boiling point, rather than nucleating around dissolved impurities at the normal boiling point and producing the necessary steam when it hits the soleplate. It has been suggested that this superheated (distilled) water in an iron will flash boil when disturbed (as with moving an iron), and cause the iron to spit, leak, and possibly scald the user. However, a mainstream iron manufacturer has a more basic explanation; simply put, distilled water does not contain the minerals necessary to help the water vaporize on contact with the soleplate.
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.
In addition, some home brewers, who are interested in brewing a Traditional European Pilsner, will dilute their hard water with distilled water so as to mimic the soft waters of Pilsen.
Distilled water is also used in Constant Positive Airway Pressure (CPAP) machines. These machines are used by people with sleep apnea to help breathing throughout sleep cycles. The water evaporates and is used to humidify the air going into the user's nasal cavity, mouth, and throat. Distilled water will not leave any contaminants behind when the humidifier in the CPAP machine evaporates the water.
Equipment to distill water 
Up until World War 2, 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, 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 was in widespread use for ships and portable water distilling units  during the latter half of the century. Modern vessels now use flash-type evaporators to boil sea water, heating the water to between 70-80°C and evaporating the water in a vacuum - this is then collected as condensation before being stored.
Drinking distilled water 
Bottled distilled water can usually be found in supermarkets or pharmacies, and home water distillers are available as well. 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 almost always contain trace components at levels, which are regulated to be safe for consumption. Some other components such as trace levels of aluminium may result from the treatment process (see water purification). Fluoride and other ions are not removed through conventional water filter treatments. However, distillation eliminates most impurities.
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 was observed that consumption of "hard" water, or water containing dissolved solids, is associated with possible cardiovascular effects. As noted in the American Journal of Epidemiology, consumption of hard drinking water is negatively correlated with (i.e., helping to prevent) atherosclerotic heart disease.
See also 
- Atmospheric water generators are used to make distilled water from air.
- Deionized water
- Heavy water
- Purified water
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- Aristotle. "Meteorology – Book II" (PDF). The University of Adelaide. Retrieved 2010-06-14.
- Trow, Charles Edward. "Chapter XVI". The old shipmasters of Salem. New York and London: G.P. Putnam's Sons. pp. 178ff. OCLC 4669778. "Short of Fresh Water Causes Alarm — Captain Williams's Invention to Make Salt Water Fresh — His 'Still' Described by him"
- Steam Iron Buying Guide. Homeinstitute.com. Retrieved on 2011-01-31.
- [dead link]
- see, for example, John Palmer's discussion of bicarbonates at: http://www.howtobrew.com/section3/chapter15-1.html
- Down the Susquehanna to the Chesapeake By John H. Brubaker, Jack Brubaker page 163
- "Navy's Compression Still Makes Fresh Water Cheap", February 1946, Popular Science
- Solar Distiller. Thefarm.org. Retrieved on 2011-01-31.
- "Drinking Water Contaminants". water.epa.gov. 2011 [last update]. Retrieved October 25, 2011.
- "EWG's Drinking Water Quality Analysis and Tap Water Database | Environmental Working Group". ewg.org. 2011 [last update]. Retrieved October 25, 2011.
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- Kozisek, F (2005 [last update]). "Health risks from drinking demineralised water (application/pdf Object)". who.int. Retrieved October 25, 2011.
- Azoulay, Arik; Garzon, Philippe; Eisenberg, Mark (2001). "Comparison of the Mineral Content of Tap Water and Bottled Waters". Journal of General Internal Medicine 16 (3): 168–175. doi:10.1111/j.1525-1497.2001.04189.x. PMC 1495189. PMID 11318912.
- Voors, A. W. (1971). "Mineral in the municipal water and atherosclerotic heart death". American Journal of Epidemiology 93 (4): 259–266. PMID 5550342.