Difference Between Deionized And Distilled Water

Deionized and distilled water are two popular types of purified water. These waters are widely used in various applications, from laboratory experiments to industrial processes. Both deionized and distilled water have undergone specific treatments to remove minerals, sediments, and other impurities. But while the methods used to purify them may be similar, some differences between deionized and distilled water make each suitable for different purposes.

Distilled water is essentially vaporized into steam and then cooled back into liquid form, which leaves behind any minerals or other contaminants that may be present. Deionization, conversely, is a chemical process that removes all of the charged particles (ions) from a solution, such as minerals and salts.

What Is Distilled Water, And How Does It Work?

Distilled water is simply water that has been boiled and condensed back into liquid form. This process removes contaminants such as minerals, heavy metals, and other impurities in natural water sources. As the steam condenses, it leaves these contaminants behind, so they are not present in the distilled water.

What Is Deionized Water, And How Does It Work?

Deionized water, also known as demineralized water, is a type of water that has had its mineral ions removed. This process is accomplished by passing the water through a special filter called an ion exchange column. The filter contains resin beads that contain positively charged ions, such as sodium and calcium, which attract and bind with negatively charged particles from the water. The resulting deionized water is free of minerals and chlorine, making it ideal for laboratory use.

Difference Between Deionized And Distilled Water

  • Cost: Deionized water is more affordable than distilled water since it requires less processing.
  • Chemical composition: Distilled water consists of 99.9% pure H2O. However, deionized water results in a slightly different chemical composition as it contains some ions that were not completely removed during deionization. This can include carbon dioxide, calcium, and magnesium.
  • Formation: Deionization is a process that involves removing positively and negatively charged ions from the water, such as calcium, magnesium, sodium, chloride, sulfate, carbonate, bicarbonate, and nitrate. Distillation refers to the physical process by which contaminants are removed from the water when boiled and then condensed to form a pure liquid.
  • Usage: Deionized water is mainly used in laboratories and medical facilities for rinsing and cleaning applications. It is also used to top off lead-acid batteries, as it does not contain minerals that may corrode the battery’s terminals. Distilled water is often used as a drinking water source or for cooking. It can also be used in aquariums and for cleaning applications.
  • Purity level: Deionized water has a purity level of up to 17 megohm-cm and is often used in laboratory applications. In contrast, distilled water typically has a maximum purity level of 10 megohm-cm. Deionized water also contains fewer total dissolved solids (TDS) than distilled water – typically around 0.1 parts per million (ppm) or less, whereas distilled water can contain up to 500 ppm.
  • Conductivity: Deionized water has a much lower conductivity than distilled water. Since deionized water is entirely free of ions, it cannot transmit electricity, so its conductivity is extremely low. Distilled water, on the other hand, still contains some ions, which allow for a higher level of electrical interference when conducting experiments or tests.

Which Is Better, Distilled Or Deionized Water?

It depends on the application of water. Deionized water is generally better for most laboratory and industrial applications because it removes more ions than distilled water. Distilled water is pure but still contains some ionic contaminants due to its contact with air during the distillation process. Deionized water has been purified through a deionization resin tank to remove these ions. This makes deionized water more suitable for applications that require extreme ionic purity, such as scientific experiments and medical use.

On the other hand, distilled water is commonly used in food preparation and home brewing processes since its mineral content is low enough to achieve desired results. In addition, it is also used in car radiators, irons, and electric kettles, as it does not leave behind any impurities. Ultimately, the choice will depend on what you plan to use the water for. If you need the water to be highly pure, then deionized water is better than distilled water.


Can I use distilled water instead of deionized water?

Yes, you can use distilled water instead of deionized water. However, it’s important to note that deionized water is highly purified and contains deficient levels of ions and other contaminants, making it ideal for many applications.

Is deionized water the same as regular water?

No, Deionized water differs from regular water because it has removed its mineral ions, while regular water still contains these minerals.

Can you drink distilled or deionized water?

No, you should not drink distilled or deionized water. Both types of water are purified and contain no minerals; therefore, they lack the essential nutrients needed to sustain life. Furthermore, drinking large amounts of either type can lead to mineral deficiencies within your body.


Difference between Deionized And Distilled Water - infographic
Difference between Deionized And Distilled Water – infographic

Deionized and distilled water are different types of purified water, but each has unique properties. Deionized water has a higher purity level and a slightly acidic pH balance and is often used in laboratories for experiments or to clean medical instruments. Distilled water has been boiled and condensed, so it no longer contains any minerals or other contaminants and has a neutral pH balance making it perfect for drinking. Both distilled and deionized water are widely used in various industries, but the decision of which one to use depends on the application.

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