Deionized vs Distilled Water: What’s the Difference?

by Jay | Updated on July 26th, 2022

There are various forms of clean water competing for the title of purest. Deionized and distilled water are contenders, but you may not know what they are. Purified water must have a total dissolved solids content of 10 parts per million (ppm) or less.

Both types of water match the purified water criteria and are far below the 10 ppm guideline. So, what distinguishes these two sorts of filtered water? When should you choose one over the other, and which is the healthiest option?

deionized vs distilled water

What is deionized water?

Deionized water is utilized when laboratory-grade water is required for medical procedures, food safety work, or lab testing. All ions have been eliminated from this sort of water, and it no longer has any charge, positive or negative.

It has been fully depleted of all dissolved solids. Thus there is no nutritional value left. All minerals have been extracted. Because no contaminants are present, the water will have a different flavor and fragrance from regular water.

The ion-exchange mechanism functions similarly to a water softener but goes further. The water is passed through a specific resin that has been charged to attract all of the water’s molecules. In place of the ions that are being eliminated, hydrogen and hydroxyl molecules are exchanged.

Deionization removes all ions from water but does not filter it. This means that particulates, bacteria, and chemicals will remain after the treatment.

As a result, deionized water is frequently filtered through a reverse osmosis membrane before being filtered through the charged resin. This guarantees that just ions are left to be extracted by the resin. Unfortunately, this resin is used in water softeners; this resin cannot be regenerated and has a limited usable lifespan.

Deionized water will pick up anything it comes into contact with because it is a blank slate. So, for example, it can pick up metals from pipes if it is transported through them.

Regular water contains minerals that prevent hazardous compounds from accumulating, but because deionized water lacks these minerals, it can easily pick up poisons from any source. This indicates it’s not ideal for drinking, especially if it’s been deionized and passed through plumbing.

Can you drink deionized water?

No, deionized water should not be consumed. It contains no minerals or salts but is corrosive to your teeth’s enamel and delicate tissue.

Why is deionized water bad for you?

The following are some of the most serious dangers linked with deionized water: Because deionized water lacks ions, it can absorb the ions in your body when you drink it. In addition, because magnesium and calcium are easily absorbed by deionized water, it can also rob these tissues.

What is the purpose of deionized water?

Deionized water, sometimes DI water, implies that all ions have been eliminated. This is critical for applications that require the purest water possible. Because of its great purity, deionized water is preferred in various applications.

Deionized water is preferable in laboratory applications since it is pure and will not interfere with test results. Deionized water assists in industrial circumstances involving machining or high temperatures because of its low conductivity, which helps lower temperatures during manufacturing.

Deionized water benefits the motor’s longevity in automotive applications, such as coolant systems. In addition, deionized water is favored because of its resistance to electricity due to the lack of charged ions to carry a charge.

Industries and products that use deionized water

  • Cleaning electronic devices
  • Cooling systems, such as ones used for laser welding
  • A/C fire extinguishers
  • Immersion cooling applications
  • Automotive applications
  • Electrical Discharge Machining
  • Pharmaceuticals
  • The beverage industry
  • Cosmetic products
  • Liquid detergents
  • Biochemistry applications

What is distilled water?

Distilled water is purified water that has been cooked and collected as steam. Therefore, all contaminants such as bacteria, silt, and protozoa will be left behind when water is transformed into steam.

After that, the steam is condensed in a condenser. The steam in the condenser will then be cooled by a fan, returning it to a liquid condition. As the steam drops condense into water, they will pass through a carbon postfilter, the final filtering stage.

This filter will catch any contaminants that have boiled away with the water. After passing through this final filter, the water will be collected and thoroughly distilled.

All pollutants and minerals are removed from distilled water. There is only one part per million of dissolved solids in it. It does, however, contain ions that can be eliminated during deionization.

Why can’t you drink distilled water?

The primary hazards of consuming just distilled water are a lack of dissolved minerals like magnesium and calcium. Some disadvantages of drinking only distilled or low mineral water include a bland flavor that many people find unpleasant, resulting in decreased water consumption.

What is distilled water used for?

Even if you do not intend to drink distilled water, there are several useful applications for distilled water around the house. They often work more efficiently when you use distilled water with medical equipment like CPAP machines and humidifiers.

Distilled water will help your iron clothes, and it normally passes vehicle specifications for car maintenance. Distilled water is also commonly advised for aquariums and can be used to water houseplants.

When should one be preferred over the other?

Deionized water is the method when ultra-pure water with no charge is required. As a result, it is the finest choice for laboratory experiments, cleaning industrial gear, aquariums, and other applications. In addition, deionized water will not corrode like ordinary water. But, of course, it will need to be treated by means other than deionization to be effective in most of these cases.

Distilled water is still extremely pure, but not to the same extent as deionized water, which has removed all ions. You wouldn’t want to drink deionized water, of course. It tastes horrible because it lacks all minerals and is bad for your health.

Because it lacks ions, it can take ions from your body, depriving you of important minerals. While distilled water still lacks important minerals found in water, it does not deplete your body of ions as it travels through you. This indicates that while distilled water is better for drinking, it is still not the greatest water to consume.

What is removed from either of these processes?

Both distilled water and deionized water are extremely pure. However, the cleanliness of the water before it goes through the water treatment makes a difference in each scenario. For example, the deionization procedure eliminates ions — charged non-organic particles – from water.

The water should be filtered first to eliminate organic debris, and then reverse osmosis (RO) system should be used to remove a considerable amount of additional impurities. This merely leaves a trace of ionized minerals for the DI system to eliminate.

On the other hand, water distillation can remove contaminants other than ions. This method removes nearly all minerals, many chemicals, and the majority of germs.

However, this does not guarantee that it removes everything, especially if the water contains volatile organics and other pollutants. These pollutants will evaporate and become part of the distilled water. Therefore, pre-treatment filtering, as with deionized water, is critical.

The price difference: Deionized water vs. distilled water

When extremely high purity water (double or triple distilled) is not necessary, many people comparedeionized and distilled water costs. The distillation process can be time-consuming, particularly when significant amounts of water must be boiled, cooled, and collected.

This technique also necessitates using fuel to heat the water and a sterile container to store it in. When distilled water is exposed to air for an extended period, it effectively becomes deionized water.

Deionization, on the other hand, is a rather short process, especially if a mixed bed resin is used and the water only needs to pass through once. Therefore, many deionized water systems use two mixed bed cartridges or tanks to ensure that all ions are removed, although the process is still reasonably quick when compared to distillation.

Furthermore, because deionization is a chemical process, energy is often just required to monitor the operation and transport the water through the system. If the DI resin is regenerated on-site, it might add time and cost to the process.


Although they may sound similar, distilled water and deionized water are not the same things. Therefore, all ions have been removed from deionized water, which is neither positively nor negatively charged.

Other pollutants, such as bacteria, chemicals, and viruses, may still be present. Because of the lack of ions, it is not a healthy beverage to drink because it can deplete your body of necessary ions. Furthermore, it does not taste nice.

Distilled water is made by boiling water to remove pollutants and then collecting the steam to condense back into the water. This procedure eliminates everything from the water, leaving only one part per million dissolved solids in the purified water.

Ions are still in distilled water; thus, drinking it will not deplete your body’s nutrients. However, it will also not restore any important minerals, so keep that in mind if you begin drinking it.

Both forms of water are suitable for laboratory work, but because deionized water is free of charge, it is frequently used in the circumstances requiring high levels of water cleanliness.


Self assessed Germaphobe, specializing in everything water, water filters, health and nutrition. Diagnosed with Type 2 Diabetes, I've acquired immense amount of knowledge when it comes to natural, biology, and everything about human anatomy.