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Demineralized Water vs Distilled Water

Demineralized Water vs Distilled Water
Written by Callum Strempel

Demineralized water and distilled water may have some similar cases of applications, but they are processed differently.

Here we will look into how exactly they differ and when to use these two common types of purified water.

What’s demineralized water?

Demineralized water is water that has undergone a mineral and salt removal process. For this process to work, water must pass through ion exchange resins that replace the cations and anions in water with hydrogen and hydroxide, which then combine together to form pure water.

What’s distilled water?

In this process, water is heated up to the point of bubbling and then the steam is removed and cooled to make distilled water. This filtration technique is commonly used and delivers water free of chemical and mineral components.

Distilled water is significantly cleaner as almost 99.9% of its toxins are successfully taken out.

Demineralized Water vs Distilled Water: How They Differ

1. Molecule

  • Demineralized water

The pH level of demineralized water is 7.0 but it is slightly acidic because the carbon dioxide in the water is released until it reaches a dynamic equilibrium. Carbonic acid occurs when dissolved carbon dioxide reacts with water.

  • Distilled water

Distilled water has a pH level of 5.5 and 6.9, depending on the duration of its exposure to air. If left open in the air, the pH may fall below 5.5.

2. Processing cost

  • Demineralized water

It doesn’t take much to prepare demineralized water since it requires low-powered energy pumps. The chemicals needed to regenerate the resin are also easily affordable.

  • Distilled water

Distillation can be expensive to heat, cool, circulate and obtain a huge amount of water for industrial purposes.

Although innovations such as multiple-effect distillation systems and steam compression have led to greater energy efficiency in the last decade, they are still expensive to operate.

3. Uses

  • Demineralized water

The common applications include –

  • Industrial use for scientific and engineering purposes,
  • Pharmaceutical manufacturing,
  • Laboratory applications and tests,
  • Laser cutting,
  • High-pressure boiler feeding,
  • Automotive uses such as acid batteries and cooling systems,
  • Cosmetics,
  • Aquariums,
  • Fire extinguishers.
  • Distilled water

Purity is important when it comes to distilled water.

  • Medical tools (certain medical devices such as CPAP),
  • Laboratory tests,
  • Cosmetics,
  • Car cooling systems,
  • Irrigation plants.

Note: Distilled or demineralized water is not recommended for human consumption.

4. Benefits

  • Demineralized water

Demineralized water is mainly used to disinfect containers and equipment. It’s also common to see its application in the production of pharmaceuticals and cosmetics products for enhanced quality and safety. You’ll find its use in boiler supply and steam production as well for the energy sector.

  • Distilled water

Although not recommended for regular consumption, distilled water helps prevent kidney stones and any unpleasant chemicals, viruses, and bacteria present in tap water. You can also protect your teeth from too much fluoride and improve your immune system by consuming distilled water.

5. Health risks

  • Demineralized water

Drinking demineralized water may increase the risk of sudden death. There may also be –

  • An increased risk of toxicity
  • Poor hydration
  • Direct impact on the digestive tissue layers, gluconeogenesis, and mineral homeostasis
  • Low intake of necessary elements from low-mineral water
  • Distilled water

As there’s no mineral component, the taste is dull that many find unpleasant. Drinking too much distilled water can reduce the metabolic function of the body and increased urine output could cause electrolyte imbalance.

6. Mineral components

  • Demineralized water

Demineralized water is low in mineral and soft water because it contains only small amounts of dissolved minerals, such as calcium and magnesium – the main cause of the hardness.

  • Distilled water

Distilled water is mineral-free and you need to add certain minerals, such as iron, zinc, potassium, sodium, magnesium, and calcium.

Calcium, magnesium, potassium, and sodium are the main electrolytes that help restore your fluid balance. These nutrients assist with the proper working of your heart, muscles, and brain.

Can demineralized water be used in place of distilled water?

There are a lot of differences between demineralized and distilled water. You can replace demineralized water with distilled water in applications like aquariums, cosmetics, car cooling systems, and laboratory tests.

Since both demi and distilled water have their ions and contaminants removed, they help prevent corrosion that ultimately enhances the lifespan of your appliances.

What’s best for batteries?

If you have to top up your vehicle battery, distilled water is ideal since it is free of metal and mineral components.

Demi water can filter and remove metals and minerals too that can interfere with your battery but distilled water is always the first choice here.

What’s best for radiators?

Distilled water is the best choice here. The fewer things are in the water except for water, the less stuff there will be to react and corrode. Distilled water is also much better at heat transfer compared to antifreeze/coolants.


Q. Is boiled water demineralized?

Demineralized water is also called deionized water. It is not quite the same as distilled water. Distilled water is filtered by boiling and re-liquefying.

Q. Can I substitute boiled water for distilled water?

Are the boiled water and distilled water the same? No, they’re not the same. Boiled water is essentially water that has expanded the temperature until it has arrived at its edge of boiling over, which kills microbes.

Q. Is tap water demineralized

Demi water is the water that has had the greater part of its mineral substances eliminated. While demi water is important for specific industrial and business applications, a large portion of the water entering your home contains dissolved minerals.

Q. Is rainwater distilled water?

Rainwater isn’t distilled water. Rainwater is the purest type of water on the planet, yet because of a few phases of the water cycle, it very well may be unsafe. Rainwater can absorb different gasses from the atmosphere and at times rainwater contains acids like sulfuric acid or hydrochloric acid.

About the author

Callum Strempel

Licensed Plumber

Hi, I’m Callum, a full time plumber with a plumbing license issued by my state. So far, I’ve spent nearly a decade and a half installing and fixing a wide variety of plumbing components and units. My profession inspires me to talk about the kitchen and bathroom (and the plumbing system) so confidently and knowledgeably that I offer my free consultations to help neighbors and fellow homeowners every now and then. As I enjoy installing faucets, sinks, showers, and fixtures, I love to see people enjoying services from those components for years to come. So, I write every week to inform you and others. Will you mind going through some of my articles on this website?

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