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Home » Water Education & Testing » Deionized Water vs Distilled

Deionized Water vs Distilled

By: Stephanie Nielsen
Last Updated:

Deionized water and distilled water are both purified forms of water, but they differ in their purification processes and applications. While both are commonly used in various industries, their methods of production and characteristics set them apart. 

Understanding these differences is crucial, especially when choosing the right type of water for specific tasks. This article delves into the specifics of deionized water vs distilled, their pros and cons, and their differences.

Key Takeaways:

  • Deionized water is purified by removing ions, while distilled water is purified through boiling and condensation.
  • Both types of water have specific uses and benefits.
  • It’s essential to understand their differences before choosing one over the other.
  • While both are forms of purified water, their applications and suitability can vary based on the requirements.
infographic of deionized vs distiled water

What Is Deionized Water?

Deionized water, often referred to as “DI water,” is water that has undergone a purification process to remove its ions.

This is achieved through a method called ion exchange, where unwanted ions are swapped for hydrogen and hydroxide ions, resulting in water that is free from ions like sodium, calcium, iron, chloride, and sulfate.

The ion exchange process involves passing water through resin beds filled with ion exchange resins.

These resins are tiny beads that are charged either positively (cationic) or negatively (anionic). As the water flows through these beds, the cations and anions in the water are attracted to the oppositely charged resins, effectively removing them from the water. 

Once the resins are saturated with ions, they can be regenerated using a solution of acid or base, allowing them to be used multiple times.

Here’s a very helpful video of Mark Timmons from US Water Systems explaining more about DI water:

Characteristics of Deionized Water:

  • High Purity: Deionized water is one of the purest forms of water available, especially when it comes to ionic content.
  • Reactive Nature: Due to its high purity, deionized water can be very reactive. It can leach minerals from materials it comes in contact with, making it essential to store and transport it in suitable containers.
  • Variable pH: The pH of deionized water can vary based on the specific ion exchange process used and the ions present in the source water. However, it’s often close to neutral.

Applications of Deionized Water:

Deionized water is widely used in various industries and applications, including:

  • Laboratories: For experiments and processes where ionic purity is crucial.
  • Electronics Manufacturing: In the production of semiconductors and microchips, even minute amounts of ions can interfere with the manufacturing process.
  • Pharmaceuticals: In the formulation of certain drugs and solutions.
  • Automotive: For topping up lead-acid batteries and in cooling systems.
  • Cosmetics: In the formulation of certain cosmetic products to ensure purity.

It’s worth noting that while deionized water is exceptionally pure in terms of ionic content, it might still contain non-ionic contaminants, such as bacteria or organic molecules, unless additional purification steps are taken.

Pros of Deionized Water

  • High purity level: Ideal for applications that require water free from ionic contaminants.
  • Suitable for laboratory applications: Used in labs where ionic purity is crucial.
  • Less corrosive than regular water: The absence of ions reduces its corrosiveness.

Cons of Deionized Water

  • Not recommended for drinking: Lacks essential minerals beneficial for health.
  • Can be aggressive: Due to its high purity, it can leach minerals from containers or pipes.

Can I Make Deionized Water at Home?

While it’s possible to make deionized water at home using ion exchange resins, achieving industrial-level purity is challenging. Specialized equipment and knowledge are required for optimal results.

What Is Distilled Water?

Distilled water is a form of purified water that has been boiled to produce steam, which is then condensed back into liquid form in a separate container.

This process effectively separates the water from most of its impurities, including salts, minerals, and other contaminants.

The distillation process involves heating water to its boiling point, causing it to vaporize. As the water vapor rises, it leaves behind impurities in the boiling chamber.

The vapor is then directed into a cooling system, where it condenses back into liquid water. This newly formed water is collected in a separate container, resulting in distilled water.

distilling water

Characteristics of Distilled Water:

  • High Purity: Distilled water is free from most impurities, including salts, minerals, and many types of bacteria and viruses.
  • Neutral Taste: Due to the absence of minerals and salts, distilled water can taste flat or bland.
  • Slightly Acidic pH: The distillation process can lead to the release of carbon dioxide from the water, making distilled water slightly acidic with a pH often below 7.

Applications of Distilled Water:

Distilled water is used in a variety of settings and applications, including:

  • Medical Field: For sterilization processes and in the formulation of certain medical solutions.
  • Laboratories: As a solvent and for experiments requiring high-purity water.
  • Cooking: In recipes that require pure water without any mineral taste.
  • Beverage Industry: In the production of certain beverages to ensure consistency in taste.
  • Household: In steam irons to prevent mineral buildup and in humidifiers.

While distilled water is highly pure, it’s essential to note that not all contaminants are removed through distillation. Some volatile organic compounds (VOCs) with boiling points close to or below that of water can still be present in distilled water unless additional purification steps are taken.

Pros of Distilled Water

  • High purity: Almost all contaminants are left behind during the distillation process.
  • Suitable for medical applications: Often used in medical settings due to its purity.
  • Free from most contaminants: Including bacteria, viruses, and most chemicals.

Cons of Distilled Water

  • Can taste flat: The absence of minerals can make it taste bland.
  • Not always free from all contaminants: Some volatile compounds might still be present.

Can I Make Distilled Water at Home?

Yes, distilled water can be made at home using a stovetop and condensation method. However, the purity might not match commercially distilled water, and some contaminants might remain.

Resource: Top Rated Water Distillers

What Is the Difference Between Deionized Water and Distilled Water?

FeatureDeionized WaterDistilled Water
Water TreatmentIon exchangeDistillation
Health ImpactNot for drinkingSafe for drinking, but lacks minerals
ContaminantsFree from ionsFree from most impurities
UsesLaboratories, some industriesMedical, cooking, drinking
CostVaries, often more expensiveTypically less expensive

Water Treatment

Deionized water undergoes ion exchange to remove its ions, including cations like sodium, calcium, and iron, and anions such as chloride and sulfate. On the other hand, distilled water is purified through a process of boiling and condensation, where the steam is collected and condensed back into liquid form, leaving most impurities behind.


Deionized water has a neutral taste, largely because it lacks ions and minerals. Distilled water can taste flat or bland due to the absence of minerals and salts that typically give water its characteristic taste.

Health Impact

Deionized water is not recommended for drinking as it lacks essential minerals beneficial for health and can be aggressive, potentially leaching minerals from the body. Distilled water is safe for drinking but lacks the minerals found in natural water sources, which can be essential for the body.

Keep Reading: Is Distilled Water Safe to Drink? – Full Guide


Deionized water is free from ions, making it suitable for applications where ionic purity is crucial. However, it might still contain some non-ionic contaminants. Distilled water is free from most impurities, including bacteria, viruses, salts, and minerals, but some volatile compounds might still be present.


Deionized water is primarily used in laboratories and some industries where ionic purity is essential. Distilled water has a broader range of applications, including medical settings, cooking, and drinking.


The cost of producing deionized water can vary, but it’s often more expensive due to the specialized equipment and resins required for ion exchange. Distilled water is typically less expensive to produce, especially on a commercial scale, but prices can vary based on the source and brand.

Deionized vs. Distilled Water: Which Is Better?

The debate between deionized and distilled water often boils down to the specific application and the level of purity required. Both types of water undergo rigorous purification processes, but they differ in their methods and the impurities they effectively remove.

Deionized Water

Deionized water is produced through ion exchange, a process that removes ionic impurities. This makes it exceptionally pure in terms of ionic content, making it the go-to choice for applications where ionic purity is paramount, such as in certain laboratory experiments or electronics manufacturing. 

However, it’s worth noting that deionized water might still contain non-ionic contaminants, such as bacteria or organic molecules unless additional purification steps are taken.

Distilled Water

Distilled water is purified through distillation, a process that involves boiling water and then condensing the steam back into a liquid. This method effectively removes a broad range of impurities, including salts, minerals, and many microorganisms. 

Distilled water is often used in medical settings, cooking, and for drinking, especially in areas where the local water supply might be contaminated.

Which Is Better?

The answer isn’t straightforward and largely depends on the intended use:

  • For Drinking: Distilled water is generally considered safer for consumption. While deionized water isn’t harmful in small amounts, its lack of essential minerals and potential to leach minerals from containers makes it less ideal for regular drinking.
  • For Laboratory Use: Deionized water is often preferred due to its ionic purity, especially in experiments sensitive to ionic contaminants.
  • For Industrial Use: The choice between deionized and distilled water will depend on the specific requirements of the industry. For instance, electronics manufacturing might favor deionized water, while food and beverage production might opt for distilled water.

Neither type of water is universally “better” than the other. Instead, the best choice depends on the specific needs of the application and the level of purity required.

Final Thoughts

Both deionized and distilled water offer high levels of purity, but they serve different purposes. Before choosing one, it’s essential to understand the specific requirements and the advantages and disadvantages of each.


Can I use deionized water instead of distilled?

Deionized water can often substitute distilled water in many applications. However, the choice depends on the specific requirements of the task. While both are purified forms, their purification methods and resulting purity levels differ.

Why do we use deionized water instead of distilled water?

Deionized water is preferred in settings requiring ionic purity, such as certain laboratory experiments. Distilled water, while pure, might still contain some ions. The choice between them hinges on the application’s specific purity needs.

Is it OK to drink deionized water?

Deionized water isn’t recommended for regular consumption due to its lack of essential minerals. Its high purity can also leach minerals from containers or the body. Natural mineral water or purified drinking water is a safer choice for daily intake.

What is better distilled or ionized water?

For drinking, distilled water, free from most contaminants, is generally preferred. Ionized water undergoes a pH-altering process, producing alkaline or acidic water. The choice between them depends on the intended use and specific health or purity considerations.

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Stephanie Nielsen
Stephanie worked as a department supervisor of kitchen, bath, and appliances at Home Depot, and water filters were part of the inventory she was responsible for assisting clients with so she learned the ins and outs of matching the right filtration device to homeowner’s needs. She also worked closely with Culligan water to educate customers about whole-home water treatment and softener systems.

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