What is Demineralized Water? Demineralized Water System

Are you curious about what demineralized water is and whether it’s safe to drink? Interested in how to get cost-effective demineralized water? Still unsure about the differences between demineralized, distilled, deionized, and softened water? In this article, we’ll answer all these questions for you.

➣What is Demineralized Water?

Demineralized water, also known as DM or demin water, is typically obtained through ion exchange. During the ion exchange process, the majority of minerals and ions in the water are removed, resulting in demineralized water that lacks calcium, magnesium, sodium, chloride, sulfate, nitrate, and bicarbonate ions. It is suitable for laboratory, industrial, cleaning, and electronics manufacturing applications.

What is Demineralized Water

The parameters for DM water limits may vary depending on specific application requirements. Demineralized treated water has a neutral pH, typically ranging from 6.5 to 7.5. It has low conductivity, usually between 1 and 5 µS/cm. As minerals and most ions are removed from the water, it is soft water, with total dissolved solids (TDS) generally below 5 mg/L. Additionally, demin water is pure and does not contain dissolved substances that induce oxidation-reduction reactions, resulting in an oxidation-reduction potential close to zero.

➣Is Demineralized Water Safe to Drink?

Processed demineralized water does not pose direct hazards, but we do not recommend it for everyday drinking for the following reasons:

1)Lack of essential trace minerals: Demineralized water lacks important mineral ions such as calcium, potassium, and magnesium, which are essential for human health. Long-term consumption may lead to deficiencies in essential trace elements and potentially impact overall health and growth.

2)Less economical: The production cost of deionized water is higher due to its stricter quality requirements, which involve complex processes such as membrane filtration and ion exchange to remove minerals and other substances from the water. In comparison, mineral water is sourced from natural springs and undergoes simpler processing, resulting in lower production costs.

3)Potential health threats: The quality standards for demineralized water are not uniform. If the source water is contaminated, processed demineralized water may contain harmful microorganisms, suspended solids, heavy metals, and other substances that pose risks to human health.

4)Corrosiveness: Demineralized water has low conductivity and can absorb gases from the air, becoming acidic and potentially corroding metal containers and pipes. Using containers made of non-corrosive materials may shorten their lifespan.

Is Demineralized Water Safe to Drink

➣What are the Advantages of Demineralized Water?

  • High Purity: Demineralized water, produced through advanced water treatment, is pure and suitable for medical, pharmaceutical, laboratory, and semiconductor industries, ensuring data accuracy and product quality.
  • Low Conductivity: With minimal soluble ions, demineralised water serves as a battery electrolyte, extending battery life and enhancing performance.
  • Customized Production: Tailored to specific needs, demineralized water systems produce water of varying purity for diverse applications.
  • Excellent Cleaning: Free from hardness ions, demin water leaves no residue during cleaning, ideal for spotless cleaning.
  • Reduced Scaling: Without minerals that cause scaling, demineralized water significantly reduces scale buildup in pipelines and equipment.
  • Improved Efficiency: By minimizing scale buildup, dm water enhances heat exchange efficiency and equipment stability.
  • Extended Lifespan: Its low corrosiveness minimizes damage to metal equipment, thus extending its lifespan and reducing the need for water treatment agents.

➣How to Make Demineralized Water?

The process of producing demineralised water is not singular. Below, we’ll detail six common demineralization techniques:

1)Ion Exchange

Ion exchange, one of the most common water treatment methods, is suitable for large-scale industrial and commercial applications due to its cost-effectiveness. It involves resin beads carrying cations (usually H^+) and anions (usually OH^-) that undergo ion exchange reactions with ions in water.

Anion exchange resins react with anions in water (such as chloride, carbonate, and sulfate ions), while cation exchange resins react with cations in water (such as calcium, magnesium, iron, and potassium ions). The resins adsorbed unwanted ions, while hydrogen ions and hydroxide ions released from the resin combine to form water molecules (H2O).

Water Deionizer Work Flow

This technique includes mixed bed ion exchange and dual bed ion exchange. In mixed bed ion exchange, both cation and anion exchange resins are mixed in a single bed, while in dual bed ion exchange, the system contains separate beds for cation and anion exchange. The choice between mixed bed and dual bed ion exchange depends on specific application requirements.

2)Reverse Osmosis (RO)

RO technology achieves desalination rates exceeding 90%. It uses high pressure to push feedwater containing dissolved salts and minerals through an RO membrane, typically with pore sizes ranging from 1 to 10 nanometers. By selectively allowing water molecules to pass through the membrane while rejecting ions, desalination is achieved.

This method not only removes ions but also effectively eliminates impurities such as microorganisms, bacteria, heavy metals, and organic compounds. It produces high-quality water with cost-effectiveness, making it suitable even for household under-sink systems, providing clean drinking water.

How Reverse Osmosis Remove PFAS

3)Electrodeionization (EDI)

EDI combines electrochemical and ion exchange technologies. By applying direct current in an electrolyte solution, an electric field is created, driving ion movement. In an EDI system, ion exchange membranes and ion exchange resins alternate to form concentrate and dilute compartments. The resins adsorb ions from water, gradually saturating over time. The electric field helps release adsorbed ions from the resins for regeneration, continuing ion removal. As a result, the resin increases water conductivity.

Under the influence of the electric field, ions in water migrate toward respective electrodes through selective ion exchange membranes. Cations move toward the cathode, while anions move toward the anode. Selective ion exchange membranes allow only target ions to pass through—cation exchange membranes permit only cations, while anion exchange membranes permit only anions. Ultimately, ions are collected in the concentrate compartment and discharged as wastewater, while the dilute compartment’s water has reduced ion concentration, yielding ultrapure  water.

edi process

Compared to traditional ion exchange systems, EDI requires no regeneration steps. It can be combined with RO systems to produce ultrapure dm water, expanding its applications, although it comes at a higher cost. It’s suitable for industries such as seawater desalination, industrial wastewater treatment, electronics, and power.

4)RO-DI Systems

As an efficient water treatment technology, RO-DI systems combine reverse osmosis (RO) and deionization (DI) technologies. DI further removes ions remaining in the RO process, enhancing water purity and reducing total dissolved solids (TDS), especially suitable for high-purity water applications.


Distillation involves heating feedwater to its boiling point (212 degrees Fahrenheit at standard atmospheric pressure) to convert it to steam. The steam then condenses into liquid (distillate) after cooling, which is collected and stored as distilled water.

During distillation, water’s boiling point is lower than that of dissolved ions, minerals, and impurities present. Therefore, the distillation process effectively removes various ions and impurities from water, achieving demineralization and producing pure demineralized water.

Figure 2 Distillation process

➣Is There any Limit toDemineralized Water?

As mentioned earlier, demineralized water may contain corrosive substances, suspended solids, bacteria, viruses, and organic pollutants, posing potential risks to human health. Additionally, its production and purchase costs are higher due to the need for specialized equipment and technology, along with significant energy consumption and potential environmental impact from wastewater generation.

However, we can find more cost-effective and environmentally friendly solutions by clearly defining requirements and exploring options. Customized systems tailored to specific needs can help reduce initial investments and operating expenses. Moreover, implementing wastewater recycling can mitigate environmental concerns.

➣What is Demineralized Water Used For?

Demineralized(DM) water, with its minimal ion content, finds widespread applications across various commercial and industrial sectors.

-In the food industry, it serves as a source for producing beverages like beer, juices, mineral water, as well as for preparing seasonings and flavorings to meet quality standards.

-In biopharmaceuticals, it’s used for producing injectable water, drug formulations, intravenous fluids, as well as diluting and preparing culture media and rinsing agents.

Demineralized Water for lab

-In cosmetics, the high purity of demineralized water ensures the quality and safety of products like lotions, creams, masks, and toners, enhancing brand trust and consumer satisfaction.

-In electronics and chemicals, ultra-pure deionized water is utilized for cleaning electronic components and manufacturing equipment surfaces, suitable for precision processes like computer chip and semiconductor production. It’s also used for diluting industrial wastewater, reducing treatment costs.

-In laboratories and healthcare, DM water is employed for preparing solvent reagents to ensure accurate experimental results. Kidney dialysis is a typical medical application.

-In cleaning, demineralized water is used for cleaning laboratory and medical equipment, food processing machinery, and containers to maintain cleanliness. Its lack of minerals also makes it suitable for car and glass cleaning, leaving no water spots.

-In cooling systems, using di water reduces scale buildup, enhances heat transfer efficiency, prolongs equipment lifespan, and significantly lowers maintenance costs. This technology is widely applied in various fields, including fire extinguishers, automotive cooling systems, cooling towers, and steam boilers.

DM water for cooling towers

-In horticulture and agriculture, demineralized water, free from harmful chemicals and soluble salts, can be safely used for irrigation. Additionally, it’s utilized for preparing nutrient solutions and diluting pesticides.

➣What is Demineralized Water Price?

The price of demineralized water is relatively affordable. Typically, a 500-milliliter bottle may range from $0.5 to $2. However, specific prices can vary based on factors such as brand, product specifications, and regional market conditions. It’s advisable to compare dm water prices from different retailers to find the best deals.

➣Where to Buy Demineralized Water?

You’ll rarely find “demineralized water” labeled on product packaging because “demineralized” is typically used to describe the water treatment process rather than the product name. As an alternative, you can look for products labeled as “distilled water” or “purified water.”

There are various ways to purchase these products. You can search online for retailers selling purified water, or you can find demineralized water at supermarkets, convenience stores, or even home improvement stores. Here are some brands of purified water for your reference:

  • Aquafina Purified Drinking Water
  • Nestlé Pure Life Purified Water
  • Fiji Natural Artesian Water
  • Evian Natural Spring Water
  • Ice Mountain Natural Spring Water
  • Poland Spring Natural Spring Water

➣What is Demineralized Water Plant and How Much does It Cost?

A demineralized water plant, also known as a deionization plant, is a system used to produce demineralized water. This equipment efficiently removes soluble minerals and salts from the raw water. Typically, the design and process selection of the system depend on the quality of the customer’s raw water, the desired water quality of the product, and the processing capacity. Therefore, there is no fixed price, configuration or standard dm water plant process flow diagram.

The diagram below illustrates a common process flow diagram for a DM water plant using ion exchange technology.

dm water plant process flow diagram

Generally, the price range for a small-scale laboratory demineralized water plant is between a few thousand to several tens of thousands of dollars. However, for industrial-scale applications, prices can range from tens of thousands to even millions of dollars. This significant cost variation is due to factors such as technical complexity, processing capacity, design fees, onsite installation, and maintenance costs.

Therefore, before purchasing a demineralized water system, it’s advisable to consult with water treatment experts, providing detailed water treatment requirements to ensure the selection of the most cost-effective solution.

➣The Future Research and Application Directions of Demineralized Water

Water treatment technologies will undoubtedly continue to innovate and optimize, achieving significant progress in various fields, and demineralization technology is no exception. While demineralized water currently has some drawbacks and limitations, future research directions may focus on reducing its impact on human health and the environment, as well as lowering production costs, to meet the evolving challenges of water resources and broader water treatment needs.

We can anticipate that demineralization technology will increasingly integrate with renewable clean energy sources such as solar and wind power. This integration will enable demineralized water production and usage in remote areas and environments with limited access to electricity, saving energy costs and reducing carbon emissions.

Furthermore, with the continuous development of digital technology, artificial intelligence, and data analytics, we expect demineralized water system production and distribution processes to become more automated. Through remote monitoring and adaptive control, systems can achieve high levels of automation, reducing labor costs and improving overall operational efficiency and equipment reliability.


Demineralized water is highly pure. When designing technical solutions or selecting the best demineralization system, you need to consider the intended use of the produced water and the quality of the feed water. You can contact NEWater for consultation on any questions you have about demineralized water. We can recommend the most cost-effective water demineralizers.


Demineralized Water vs Deionized Water, What is the Difference?

These two types of water are both purified and share similar characteristics and uses, as they typically contain minimal minerals and most ions have been removed. Therefore, they are generally regarded as the same type of water, and the terms can be used interchangeably. However, slight differences in their characteristics may arise depending on the specific production processes.

What is Distilled Water?

Distilled water is purified through a distillation process, resulting in very high purity with minimal impurities. It is commonly used as cooling water, for preparing chemical reagents, as laboratory-grade water, and for cleaning electronic components, among other applications.

Is Demineralized Water and Distilled Water Same?

Demineralized water and distilled water both belong to the category of high-purity water, but there are some differences between them. You can learn more through this article: deionized water vs distilled water

Demineralized water, also known as deionized water, is primarily aimed at removing most of the ions from water. Although demineralized water can achieve high purity, it may still contain impurities such as microorganisms and suspended particles. The purity of DM water is typically lower than that of distilled water, and the preparation methods can involve ion exchange, membrane filtration, or even distillation.

Distilled water, ideally, consists purely of H2O without any impurities, but its production cost is higher. It is commonly used in fields where extremely high water quality is required.

What is the Difference Between DM Water and Soft Water?

The main difference between demineralized water and softened water lies in the extent of removal of dissolved salts and minerals in the water, as well as their respective applications.

Demineralized water, achieved through processes such as distillation, reverse osmosis, or ion exchange, effectively removes nearly all ions from the water, including calcium, magnesium, sodium, chloride, fluoride, lead, iron, manganese, etc. Due to its high purity, it is commonly used in environments with stringent water quality requirements, such as laboratories, pharmaceuticals, and electronics manufacturing.

Softened water, on the other hand, primarily utilizes ion exchange resins to exchange sodium ions in the water with calcium and magnesium ions, aiming to remove minerals and reduce water hardness. However, the softening process may still retain some minerals in the water and cannot remove other soluble salts and impurities. Softened water is typically used for household purposes requiring water softening.

What is the Difference Between Spring Water and Demineralized Water?

The difference between the two mainly lies in their sources and mineral content.

Spring water originates from natural underground sources and is typically bottled without undergoing significant processing. As water flows from underground aquifers, it carries various minerals such as calcium, magnesium, potassium, and sodium. These minerals, along with beneficial trace elements, dissolve richly in the water, making spring water suitable for drinking purposes.

Demineralized water, on the other hand, undergoes purification processes to remove minerals and ions, resulting in water with low conductivity and minimal mineral content. This type of pure water is well-suited for applications that demand high water quality standards.

What Bottled Water is Demineralized?

In most cases, bottled water undergoes processing while retaining some beneficial minerals for human consumption, becoming purified water. Few bottled water brands on the market explicitly label themselves as “demineralized water.” You can check product descriptions or consult some purified water and distilled water brands to see if their products meet your water demineralization requirements and specific needs.

Is Tap Water Demineralized?

In general, tap water has not undergone demineralization treatment and therefore is not demineralized water (DM water). You may notice limescale buildup on faucets, showerheads, and pipes, and water spots may remain on dishes washed with tap water. If you wish to demineralize tap water, purchasing a small-scale water purification system is a wise choice.

What is Demineralized Water Tank?

The demineralized water tank refers to a storage container specifically designed for storing demineralized water. It comes in various capacities and sizes for selection, commonly made of materials such as stainless steel, fiberglass, or specific types of plastic.

Update cookies preferences
Scroll to Top