Difference Between Deionized and Distilled Water

Water is the basic and important element in every living organism’s life. According to the level of purity and key features, they are classified into various types. Deionized and distilled water are one of them. Not all water types are suitable for various activities such as laboratories, medicines, and much more, so the selection of water types has to be done carefully.

Deionized vs Distilled Water

The main difference between deionized and distilled water is that deionized water focuses on removing electrically charged ions whereas distilled water focuses on removing various forms of contaminants without considering the charge. Although both are pure forms of water. Distilled water is 99.9% pure whereas the purity depends on the water quality of deionized water.

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Deionized water also known as DI water has no ions present in it making it a pure form of water. Because of its extreme purity, deionized water is expensive. The majority of ions have an electric charge on them. This charge is removed by demonizing water. As a result, it’s widely employed in a variety of industries for a variety of purposes. It has a pH of 7, but when it is exposed to the oxygen and carbon dioxide in the air, the pH comes to 5.6.

On the other side, distilled water is prepared by boiling the water into vapours, and then the condensed vapours are cooled down to form liquid again and collected in a vessel. When water starts evaporating, it leaves behind all the non-volatiles mixed in it, though some volatiles will also evaporate. The water will be nearly pure H2O after it re-condenses in a separate container.

Comparison Table Between Deionized and Distilled Water

Parameters of ComparisonDeionized WaterDistilled Water
DefinitionDeionized water is a type of pure water that has dissolved ions removed. Distilled water has the purified of contaminants by boiling it allowing it to condense in a different location.
Change of phaseNo changeLiquid-Gaseous-Liquid
Purity levelIf made from tap water then 90-99%99.9%
ConductivityLow conductivityHigh conductivity
Making processIon-Exchange method, RO methodVaporization and re-condensation

What is Deionized Water?

DI water is free from ions, these ions are mineral salts like calcium, iron, so it is also called “Demineralized water”. Some of the numerous uses in which deionized water is preferred. It does not affect test results because it is a pure form of water having low conductivity, so all the ions are removed. As a result, it’s an excellent choice for industry settings involving machinery.

Deionized water is widely utilized in specific contexts since it is the purest water available. To extend the life of a motor, deionized water is employed as a coolant system. For making medicines, “water for injection” is used, the first step is to make the water deionized. It can be achieved by various methods of purification like Ion-Exchange (IX) method, Electrodeionisation (ID), Reverse Osmosis (RO), etc.

Some of the benefits of DI water are that it is not corrosive so it will not react with metallic elements, it is simple to produce and it easily gets dilute without contaminating other solutions. It is used as a good cleaning agent for lab purposes due to its pureness. It is safe to drink DI water but not one ideal for drinking. Deionization has emerged recently from the last century when electrochemical methods for purifying water were used in studies.

What is Distilled Water?

Distilled water is a pure aspect of water that has a negligible amount of minerals, salts, and organic materials. The process of collecting distilled water is to heat the water and collect the condensed steam of the boiling water. The lack of minerals in distilled water deprives users of the essential nutrients, however, studies suggest that the majority of these minerals are obtained through food.

Even electrolytes like potassium and other minerals that your body requires are absent in distilled water, leading to missing out on micronutrients. Some studies have discovered a link between consuming calcium and magnesium-deficient water to fatigue, muscle cramps, weakness, and heart disease. Furthermore, distilled water can dehydrate you which makes it unsuitable to drink. Distilled water can be substituted by several alternatives like purified water, Reverse osmosis water, spring water, demineralized water and much more.

The following are the common application examples: It is used to sterilize hospital materials to avoid contamination and infections. Distilled water is used in laboratory tests because there is nothing in it that affects the accuracy. The water used in moisturizer, shampoo, or any other cosmetic products is always distilled water. It has non-corrosive properties that will help the automobile engines to extend shelflife.

Main Differences Between Deionized and Distilled Water

  1. Distilled water is purer than deionized water because distilled water removes every contaminant and pathogens irrespective of the charged ions in it, but in deionized water, it only removes the charged particles and not the uncharged particles like viruses.
  2. Deionized water does not conduct electricity while distilled water conducts electricity.
  3. Deionized water is corrosive whereas distilled water is non-corrosive, so it is used in the metal-working industries.
  4. Distilled water can be achieved by a simple process like boiling and condensing the water but in the case of deionized water processes like the Ion-Exchange method, the RO method is used.
  5. Distilled water is achieved by a shift in the phase whereas deionized water is not made by a change in phase.
  6. Distilled water has been used since the era’s whereas deionized water has been started using for the past hundred years.


Both types of water have their pros and cons. Deionization and distillation both create extremely pure water for specific applications. They are, nevertheless, dissimilar. Deionized water does not eradicate impartial organic molecules, bacteria, or viruses from the water, whereas distilled water does. Similarly, distilled water requires a phase transition from vapour to liquid and again to liquid, but not a chemical mixing, whereas deionized water necessitates a chemical mixture but not a condition change.

The distilled water, on the other hand, can disturb an ecosystem by equalizing the mineral percentage to which the local environment has adjusted. For deionized water, multiple deionization procedures, like counter-current and mixed-bed deionization, are employed. The least expensive procedure is counter-current, but mixed-bed delivers the purest form of water.

While distilled water is fine to drink, deionized water must not be taken. Deionized water is slightly acidic and can harm the dental enamel and soft tissues in addition to not supplying materials. After the water is exposed to air for a while, you can consume distilled, deionized water.


  1. https://www.sciencedirect.com/science/article/pii/S0925521499000502
  2. https://ascelibrary.org/doi/abs/10.1061/(ASCE)0733-9372(2002)128:3(253)
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