Demineralised Water: A Comprehensive Guide

Understanding Demineralised Water

Demineralised water is devoid of all ions, minerals, and nutrients. This ultra-pure form of water is achieved through a stringent purification process, making it free from all soluble mineral salts. Consequently, it lacks both anions and cations.

The Science Behind Its Creation

1. Processes Involved

  • Deionization: This method uses special ion-exchange resins to remove mineral ions from water. 
  • Distillation: By boiling water and capturing the resulting steam, impurities and minerals are left behind.
  • Electrodialysis: This uses electrical processes to move salts through membranes, purifying the water.


  • Membrane Filtration: Techniques such as nanofiltration or reverse osmosis employ semi-permeable membranes to remove impurities from water.

2. The Procedure

Water is channeled through an anion exchange resin in its hydroxide (OH-) form, followed by a cation exchange resin in its hydrogen (H+) form. As the water navigates through these resins, unwanted ions are swapped out, leaving behind pure water.

Demineralised vs Distilled Water

While both forms of water are pure, they’re achieved through different means. Distillation involves boiling water and then recondensing the vapor. On the other hand, demineralisation uses processes like deionization to remove ions. Distilled water might still have certain organic impurities, while demineralised water might have a slightly higher degree of mineral ion removal. Additionally, deionization results in less scale buildup compared to distillation.

Demineralised Water Plants: An Overview

These are essentially large-scale, industrial setups geared towards producing demineralised water. These plants are equipped with two pressure vessels filled with cationic and anionic exchange resins. The type of resin chosen depends on various factors like water temperature, required water quality, and existing impurities.

Detailed Process:

The water first passes through the cationic resin operating in the hydrogen cycle. During this phase, cations like calcium, magnesium, and sodium are exchanged for hydrogen ions. Next, the water flows through the anionic resin, where anions (e.g., sulfate, chloride) are replaced by hydroxide ions. The final product is water primarily composed of hydrogen and hydroxide ions.

Applications of Demineralised Water

  • Feeding high-pressure boilers.
  • Cleaning in chip manufacturing.
  • Usage in medical facilities or labs demanding high purity water.
  • In pharmaceuticals as processed water.
  • In microelectronics.

On the pH Scale

Freshly produced demineralised water boasts a neutral pH of 7.0. However, when left exposed to air, it absorbs carbon dioxide, leading to a slightly acidic pH level, typically around 6.

DIY Distilled Water

While true demineralised water requires specialized machinery, you can produce distilled water at home, which is a close substitute. The method involves boiling water in one bottle, capturing the steam in another bottle, and then allowing it to recondense. This homemade method provides an affordable way to obtain pure water, though it’s not as precise as the industrial methods.


  • Arsenic: Approx. 90% (unspecified).

  • Fluoride by 91.8% (WITHOUT extra filters).

  • Lead 97.5%

  • Benzene 99.9%

  • Chlorine 96.6%

  • Cysts 99.99%

  • Arsenic by 99.9%

  • Fluoride by 99.9%

  • Lead 97.5%

  • Benzene 99.8%

Available in 1-size only. Available in various sizes.
Plastic materials. Metal & plastic materials.
Number of filters: 3 Number of filters: 2 - 4
Filter methods: Mechanical, Reverse Osmosis & Activated Carbon filters. Filter methods: Black microporous-filters & white fluoride Filters
4-stage filter process. 2-stage filter process.
Holds a maximum water capacity of 3-quarts.2.25 Gallons
45.7 x 45.7 x 38.1 cm 19" High x 8.5" Diameter
System: 1 year limited warranty.Filters: 2 years; System: 1 year.

Where to Acquire Demineralised Water

Demineralised water is available for purchase online, with platforms like Amazon being a convenient option. Alternatively, investing in machines that produce demineralised or distilled water can be a long-term solution, reducing environmental waste from plastic bottles.
This guide offers a thorough look at demineralised water, its production, and its uses, helping users make informed decisions about its application and benefits.

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