- When water is distilled, it is heated to boiling and the steam is collected in a condenser. The condenser is surrounded with cooler water, which cools the steam and turns it back into water. Because salts are heavy, they are not contained in the steam. The water that is condensed from steam during distillation does not contain these salts.
- Distillation removes many impurities in addition to salt, including heavy metals, bacteria and viruses. It does not remove all these items, so drinking distilled water does not necessarily guarantee safety.
- There are some that believe that because distilled water contains no salts, that it should not be consumed for fear that the body's salts will be leached by the distilled water. There is no scientific basis for this claim. There are also claims that drinking distilled water will cause harm to teeth for the same reason. While distilled water does not offer the protection of tap water because of the absence of fluoride, there is no scientific reason to believe that distilled water can physically damage teeth.
- Distilled water is used preferentially in home appliances such as steam irons or coffee pots because the water does not leave behind lime scale. When tap water is turned to steam or evaporates, the minerals in the water (such as calcium and magnesium) are left behind and can form a film. Over time, these minerals can build up and cause damage to these appliances if they are not cleaned regularly.
- Some individuals may worry that removing the minerals from drinking water will be harmful. However, minerals such as calcium found in drinking water make up a very small proportion of the minerals taken in by the body daily. Thus, the effects are minimal of not intaking these minerals via drinking water.
