Distilled water is obtained by distillation, This water is free of all its minerals and micro-organisms.
Characteristics of distilled water
Since it is generally in contact with the ambient air it absorbs CO2 which dissolves forming acidic species giving it a pH of 5.4.
In addition, unless it is kept in a sterile enclosure, spores and organisms in the air will be deposited. So if it has remained exposed to the ambient environment it is not sterile water.
Distilled water is therefore not pure water (composed only of molecules of H2O).
A flask of distilled water for laboratory use. © Jesse Dill CC by-nc 2.0
Distilled water - 1 Photo