Upside(s) of Distilled Water

Aside from desalinating water, the distillation process will reliably remove bacteria and viruses and dangerous heavy metals like lead, arsenic, and mercury. Distillation is ideal for recipients of non-municipally treated water, due to the particular challenges and heavy contamination of raw, untreated water. For this reason, distillation is often used as the preferred method of water treatment in developing nations that must work with heavily contaminated, untreated drinking water. Distillation is extremely effective at the removal of bacteria and often used in areas at high risk of waterborne diseases. Distillation also removes soluble minerals like calcium, magnesium, and phosphorous that may harden water and increase the occurrence of scaling.

Downside(s) of Distilled Water

    The distillation process contains several elements that make it undesirable for purifying drinking water. First of all, while the vaporization process will strip water of salt, metals, and bacteria, the boiling point of most synthetic chemicals, including pesticides, herbicides, and chlorine solutions is lower than the boiling point of water. Synthetic chemicals are the major contaminants remaining after municipal treatment. Distillation does not remove these harmful chemicals.
      Because this process must be repeated several times to ensure significant water purity, it could take several hours to provide one gallon of cleansed water. Generally, distillation requires five gallons of tap water to generate one gallon of purified water.
     Finally, distillation, like reverse osmosis, strips water of natural trace elements. When these elements are removed from water, the hydrogen composition becomes greater in proportion, making the water very acidic. Several studies have proven that drinking distilled water, stripped of minerals, can actually be harmful to the body system. Long-term consumption of such de-mineralized water can result in mineral deficiencies in the body. Though the removal of trace minerals creates water that is ideal for use in photo or print shops, it creates tasteless and even unhealthy drinking water.

What Chemicals Does Distillation Reduce or Remove

    Distillation removes chemicals similar to those removed by reverse osmosis, but in a different manner. Distillation, through its water evaporation process, will remove any chemicals or organic materials with higher boiling points than water. Such chemicals and organic materials with higher boiling points include bacteria, minerals, trace amounts of metals, many volatile organic chemicals, and nitrate. It strips water of nearly all of its natural minerals. Many of the minerals the distillation process removes are vital to the body’s natural processes. The distillation process is not selective in its removal of minerals, and it strips water of both dangerous and valuable mineral compounds.

Important Note About Chlorine:

The distillation process alone CANNOT remove dangerous chlorine, pesticides and herbicides.  The distillation process contains several elements that make it undesirable for purifying drinking water. First of all, while the vaporization process will strip water of salt, metals, and bacteria, the boiling point of most synthetic chemicals, including pesticides, herbicides, and chlorine solutions is lower than the boiling point of water. Synthetic chemicals are the major contaminants remaining after municipal treatment. Distillation alone does not remove these harmful chemicals.

Source:  The History of Water Filters