In many ways, distillation is the reverse of boiling. To remove impurities from water by distillation, the water is usually boiled in a chamber causing water to vaporize and the pure (or mostly pure) steam leaves the non-volatile contaminants behind. The steam moves to a different part of the unit and is cooled until it condenses back into liquid water. The resulting distillate drips into a storage container.Salts, sediment, metals – anything that won’t boil or evaporate – remain in the distiller and must be removed. Volatile organic compounds (VOCs) are a good example of a contaminant that will evaporate and condense with the water vapor. A vapor trap, carbon filter, or other device must be used along with a distiller to ensure the more complete removal of contaminants.


  • A good distillation unit produces very pure water. This is one of the few practical ways to
    remove nitrates, chloride, and other salts that carbon filtration cannot remove.
  • Distillation also removes pathogens in the water, mostly by killing and leaving them behind when the water vapor evaporates.
  • No drop in quality over time – As long as the distiller is kept clean and is working properly the high quality of treated water will be very consistent.
  • No filter cartridges to replace, unless a carbon filter is used to remove volatile organic


  • Distillation takes time to purify the water. It can take two to five hours to make a gallon of distilled water.
  • Distillers uses electricity all the time the unit is operating
  • Distillers remove all of the oxygen from the water
  • Distillers require periodic cleaning of the boiler, condensation compartment, and storage
  • Countertop Distillation is one of the more expensive home water treatment methods, using $0.25 to $0.35 of electrical energy per gallon of distilled water produced – depending on local electricity costs. The cost of ownership is high because you not only have the initial cost of the distillation unit to consider, but you also must pay for the electrical energy for each gallon of water produced. If it cost you $0.25 to distill each gallon and you purified 10 gallons per week, you would pay $130 for your 520 gallons of distilled water each year.
  • Most home distillation units require electricity, and will not function in an emergency
    situation when electrical power is not available.