Understanding the Benefits and Risks of Deionized (DI) Water

Understanding the Benefits and Risks of Deionized (DI) Water

Deionized water is a drink that removes all of its ions and has no charge. It can be created by exposing conventional water to electrically charged resins that will bind and attract salts and remove them from the water.

For years, it has been used in microelectronics as well as in the field of medicine. It is a good solvent for the production of various products we have in the market today.

Some people use deionized water in their homes, while some are hesitant to buy water filters to produce one for their family.

This article aims to discuss what deionized water is and how it is made. Also, this will tackle the benefits and risks of using it at home or the office, plus the tips for using deionized water.

What Makes DI Water Necessary?

Deionized water is a true water blank, meaning it assumes the chemistry of whatever product is added. This has critical implications, especially for the medical industry.

When medical product manufacturers create a product, water is almost always mixed in. However, to create a chemically sound product, the water can’t contain any impurities that could potentially change the product’s chemical composition.

For example, suppose a chemist wants to make saline or another solution injected into the body. In that case, their water needs to meet a standard called “water for injection,” which starts with deionized water. That way, when the saline formula is added to the water, it creates a replica of the solution they need.

If the water contains any impurities or metals, such as copper or lead, it will cause adverse health effects for whoever injects the product.

Other DI Water Applications

In addition to medical product manufacturing, DI water is used today in facilities across various industries, required for a myriad of reasons.

For example, a glass manufacturer may require DI water to rinse their product after it’s complete. Using tap water would result in TDS deposits (calcium, magnesium, silica) on the glass surface.

For the biotech and pharmaceutical industries, bacteria-free water is an absolute necessity. That’s because if there is any chance that a solution or the chemical mixture could end up in a patient’s body, any amount of organic content could be of great harm.

In specimen processing, where surgical instruments are cleaned, deionized water is used in conjunction with a liquid or gas disinfectant and a microbial-free rinse to ensure that the instruments are free of any residuals, thereby ensuring absolute sterility. This is something that the use of tap water cannot guarantee.

Deionized water has removed almost all its mineral ions, resulting in bacteria-free purified water.

For many industries, like the medical and pharmaceutical industries, deionized water is the thing that helps maintain product safety and integrity.

Deionized Water

The idea of deionizing water started years ago with the scientists’ notion that water is better if it is pure.

Deionized water, also known as demineralized water, is water wherein all of its mineral ions, such as sodium, iron, calcium, copper, chloride, and sulfate, are removed. It is clean, safe, and it tastes great. Also, it does not contain any chemicals or harmful toxins.

Big manufacturing firms, pharmaceutical companies, and laboratories use deionized water in their experiments and products.

One can install a water filter in their home that uses direct osmosis to create deionized water. It can be costly. However, the benefits it gives can outweigh the price. Also, the system is easy to maintain since it only has a few accessories which you need to clean every month.

The water filter can be used in other places like hospitals, offices, and schools where the hard water is unsafe for drinking. Meanwhile, the ions lost in the process can be obtained through eating healthy fruits and vegetables in your diet.

Deionization is a chemical process that uses ion-exchange resins, specially manufactured, and exchanges hydrogen and hydroxide ions for the dissolved minerals. Then, it recombines again to form water.

The deionization process can produce highly pure water, similar to distilled water, since most non-particulate water impurities can dissolve in salt. Also, deionization does not build up the scale, making the process faster.

On the other hand, deionization cannot remove uncharged organic molecules plus bacteria and viruses, not unless you use incidental trapping in the resin. As such, deionized water can still pose health problems in the end.

But if you use specially-made and strong base anion resins, then it can remove even gram-negative bacteria. Furthermore, one can continuously and inexpensively do deionization through electro-deionization.

Meanwhile, there are three types of deionization processes: the counter-current, co-current, and mixed bed.

Co-current Deionization

The co-current deionization pertains to the original downflow process of the water. In this process, both the regeneration chemicals and the input water enters at the top of an ion-exchange column, and both exit at the bottom.

When comparing the costs, the co-current deionization costs are higher than the counter-current deionization due to the different use of regenerants. 

Regenerate chemicals are diluted as it encounters the bottom or finishing resins in an ion-exchange column. As such, the quality of the product is lower versus a similarly sized counter-flow column.

Today, this process is still used by some companies. It can be maximized by focusing on the flow of the regenerants within the ion exchange column.

Counter-current deionization

Meanwhile, counter-current deionization has two major forms that require specific engineering internals.

The first one is the up-flow columns. At this location, input water will enter from the bottom, and the regenerants will enter from the top of the ion exchange column.

Second, the up-flow regeneration. With this one, the water will enter from the top while the regenerants enter the bottom part.

In these two cases, there must be separate distribution headers that must be tuned up. The input water flow and its quality, desired product water analysis, and operation time between regenerations must be set accordingly.

Counter-current deionization is a more attractive method of exchanging ions among the three types of deionizing water.  Chemicals or regenerants

can be able to flow in the opposite direction towards the service flow. As such, there will be the lesser time needed versus the co-current deionization.

Furthermore, the quality of the final product can be as low as 0.5 parts per million. Indeed, there are various advantages of counter-current deionization. Some of which are requiring low operating costs and low usage of regenerants in the entire process.

Mixed bed deionization

Lastly, the mixed bed deionization is a mixture of anion resin and cation in a 50:50 ratio. This mixture is joined in a single ion-exchange column. It also contains mixed bed demineralizers as the final water polishing that can clean the last few ions in the water before using it.

Studies show that the water produced by the mixed bed deionization through a single pass can be the purest among all water types with proper treatment.

Small mixed bed deionization units have no regeneration power, unlike big ones. Those units that big companies use are commercial mixed bed deionization system, and it has elaborate regenerant and internal water distribution systems.

In this type of system, a controller operates the valves and the pumps so regenerants can mix with the anions and resins in the ion exchange column. Take note that each of these is regenerated separately and combined again during the regeneration process.

This kind of system is used only when the company requires the highest purity of water. It can achieve efficient and quality water through difficult and expensive regeneration.

Distilled Water versus Deionized Water

Understanding the Benefits and Risks of Deionized (DI) Water

Distilled water and deionized water are often interchanged today, but the two types of water are different.

Distillation is one of the oldest forms of purifying water, and it is still being used at the moment. The product of distilled water is pure and uncontaminated. Meanwhile, the product of deionized water is even purer than distilled water.

First of all, deionized water is created through a series of intensive water purification processes.

After the initial water cleaning process, the water goes through a reverse osmosis membrane. Then the water passes through a special deionizing medium responsible for removing the other ions left in the water.

By going through these various and intensive purification processes, the deionized water can result in pure or even purer than that distilled water.

What is the difference between distilled and deionized water that makes consumers opt for distilled water? Even if the latter even is as pure and clean as the former?

The distillation of water is a much simpler and more convenient process to undertake than the deionization of water. Here's a list of their difference: 


  • Distillation and deionization are two different ways of water purification, where the latter is far cheaper. For household use, there is no difference. Deionized water can be used for anything that traditionally required the use of distilled water. Even if it is labeled as ‘distilled water,’ it is probably deionized, not distilled.
  • While deionization removes most minerals and other inorganic ions, it does not affect organic substances or microbes. Distillation generally produces water of better purity but might not remove volatile organic compounds.
  • For use in laboratories, the pharmaceutical industry, and such, ultrapure water is sometimes needed. Historically, the purest water was obtained by double distillation. Nowadays, even higher purity can be achieved by combining several advanced methods of purification.

With the availability of water distillation countertop machines in the market, it is easier to create safe and pure water through this process than deionization, making it a far more popular option for people who want clean water without having to spend it extra money on bottled water or an extensive purification process.


When it comes to distilled water vs. deionized water, both are very pure. In each case, however, the purity of the water before it goes through the water treatment makes a difference. The deionization process, for example, only removes ions – charged non-organic particles – from the water. The water should be filtered first to remove organic material, and additional filtering with a reverse osmosis (RO) system will remove a significant number of additional contaminants. This leaves only a small amount of ionized minerals for the DI system to remove.

Water distillation, on the other hand, can remove more impurities than just ions. This process removes nearly all minerals, many chemicals, and most bacteria. However, that doesn't mean that it removes everything, especially if the water contains volatile organics and certain other contaminants. These impurities will evaporate and stay in the distilled water. As with deionized water, pre-treatment filtering is an important step.

How to Deionized Water

Simply put, deionized water is water that has all of the ionized particles removed. This is important because once you remove any organic materials from the water supply, the vast majority of dissolved impurities in modern water supplies are ions such as calcium, sodium, chlorides, etc. An ion is a molecule that has a positive or a negative charge; iron ions, for example, have a positive charge. One way to effectively purify water is to remove these ions and replace them with hydrogen (H+) and hydroxyl (OH-) ions, which combine to make water. Check out our page about what DI water is to learn more terms and definitions related to deionization.

Curious about how to make deionized water? Before passing through a deionization (DI) system, water is usually filtered and pushed through the reverse osmosis (RO) membrane. These pre-filtering steps do a good job of removing the organic matter and a majority of other contaminants. That means that the water is very clean before it enters the DI system. Check out our infographic on how RO and DI can work together.

Two ion-exchange resins are used to deionize the water. Positively charged ions (cations) and negatively charged ions (anions) are exchanged for hydrogen (H+) and hydroxyl (OH-) ions, respectively, due to the resin's greater affinity for other ions. After passing through both types of resin at least once, all that's left is highly purified water. Once depleted of exchange capacity, the resin bed is regenerated with concentrated acid and caustic, which strips away accumulated ions through physical displacement, leaving hydrogen or hydroxyl ions in their place.


Once you know to make deionized water and what deionized water is used for, you need to understand the different deionizer types. Each of these deionizer systems is effective, but some are better suited to specific industries or purposes.

There are four basic types of deionizers:

  1. Disposable cartridges
  2. Portable exchange tanks
  3. Automatic units
  4. Continuous units

A two-bed system uses separate cation and anion resin beds. Mixed-bed deionizers utilize both resins in the same vessel. Mixed-bed deionizers produce the highest quality water, but two-bed deionizers have a larger capacity. Both cartridge and portable exchange tank units can be used until the resin is exhausted, after which it is replaced. Automatic units are permanent fixtures, and the resin is regenerated on-site. Continuous deionizers, mainly used in labs for polishing, do not require regeneration.

Where Can You Use Deionized Water?

Deionized water can be used in microelectronics and pharmaceutical companies to dissolve drugs sold as medicines for the general public. It is also named as one of the main ingredients in the manufacture of healthcare products and cosmetics.

Also, deionized water is a good solvent in ceramic, glass, wood, prick, and others. Here are other uses of deionized water today:

  • Preparation of chemical mixtures and solutions in the laboratory.

  • Preparation of electrolytes for alkaline and acid-based batteries.

  • Dilution of concentrated anti-freeze chemicals.

  • Final rinsing of printed circuit boards, washing the equipment from alkalis and acids after processing the technological operations in the electronics industry.

  • Refueling the cars glasswashers

  • Topping up the cooling system. Deionized water will not create salt deposits in the system.

  • Flushing cooling systems out of automobiles.

  • It can be used in perfumes.

  • It can be used as detergent.

  • Refilling steam and iron household devices can help to avoid deposits of minerals.

  • Other industrial processes require the use of pure water.

Nowadays, the use of deionized water as a cleanser is a new technique. It does not use any chemicals, and as such, the cleanser uses water instead.

Advantages of Using the Deionized Water

Deionized water is the water of choice in many factory and manufacturing settings because manufacturers want to avoid the buildup of salts on machinery.

Deionized water may be used to cool, lubricate machines and other applications in an industrial setting.

Deionized water can be used to manufacture cosmetics, medicines, and also processed foods.

Meanwhile, some health experts recommend deionized water for short-term use only to detoxify the body. However, if you choose to detox this way, you should seek the advice of a health expert. According to the World Health Organization, they can monitor your progress to make sure you don’t overdo it.

If you are concerned with the ions lost in the process of deionization as you take the water, it can be easily obtained through eating a well-balanced meal.

Understanding the Benefits and Risks of Deionized (DI) Water

Converting Tap Water into DI Water

The process of deionization exchanges all of the charged ions found in tap water for Hydrogen and Hydroxyl ions. This process helps to form the water molecule, H2O.

The deionization or ion exchange process results in true purified water “blank”; nothing but water in its purest form.

The deionized water then takes on the characteristics of any solution or chemistry that is added to it. Good quality deionized water will measure approximately 18.2 megohms of resistivity with a temperature-compensated resistivity meter.

So how do we get there? It involves a deionization process that uses high-purity resin to initiate an exchange cycle, cleansing the water of unwanted ions. However, the configuration of equipment for this process varies widely depending on several factors.

Risk of Using the Deionized Water

Deionized water can be harmful to your health. While there are serious concerns about how deionized water can affect one’s health, it is best to use it for industrial purposes only.

Here are some of the risks that you should take note of:

Absorb Ions in the Body

First, it lacks ions, and when you drink it, it can absorb the ions in your body. It can steal the minerals in your tissues, such as magnesium and calcium, which are both easy for deionized water to absorb.

Although water is not an important source of magnesium and calcium, it can help contribute to people's daily needs. As such, you are drinking deionized water can limit your intake of essential nutrients.

Take note that magnesium and calcium are important for the development of the bones and are also good for the heart.

Understanding the Benefits and Risks of Deionized (DI) Water

Deionized Water Tastes Bad

Deionized water is free of ions and minerals. That’s why it might taste bad. Your taste buds may adjust to their taste over time. However, there is a tendency for you to seek out other beverages, such as soda and other carbonated drinks, which are bad for your health.  Also, deionized water is not a good beverage to quench your thirst, unlike other types of water.

Risk of Toxic Metals

If you get your deionized water from the tap, you may be at risk of toxic metal contamination. Deionized water is more susceptible to attracting metals found in the plumbs versus mineralized water because it is a less stable form of water.

Regular water contains magnesium and calcium, which helps prevent toxic substances in the drinking water, and this can’t be found in deionized water. Calcium and magnesium stabilize the water and act as antitoxic substances in it.

Tips for Switching to the use of Deionized Water

Since bacteria and viruses can still be present in deionized water, you can ask your local water filtration unit provider for the ideal water filtration unit that can be effective for straining bacteria and viruses. Ask about the ideal maintenance of your water filtration system at home and know the appropriate cleaning measures to be used.

Eat a well-balanced meal or take dietary supplements like multivitamins to replenish the lost ions found in water once you decide to take the deionized water.


In sum, although you can drink deionized water, always remember that not all are suitable for public consumption, according to the Illinois Department of Physics. This is because the deionized water found in the laboratory and big manufacturing companies contains specialized resins that remove the ions. As such, these resins can have harmful effects on your body.

However, if the water has a label that says that it is safe to drink, you can have it. Otherwise, don’t take products that you are not 100% sure of their safety. Also, make sure to eat a balanced diet so that the ions lost in purifying the water will be replaced by the food that you eat.

The water you drink is decontaminated and filtered to make it safe to drink. But drinking water still contains minerals, also referred to as ions, such as sodium, magnesium, and iron. Deionizing the water takes out these minerals to create more pure water. While there are uses for deionized water, removing the minerals is not always best.

If you are planning to install a water filter that can produce deionized water, always make sure that you talk with an expert and orient yourselves with the pros and cons of this type of water.

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