How a Water Ioniser Works – The Basic Principles

In this article, we are going to cover the basic principles behind the functioning of a water ioniser machine. A water ioniser is a device that splits up water molecules into smaller particles called ions. Basically, a water ioniser produces three main types of water by adjusting certain settings and parameters of the machine:

  • alkaline water
  • neutral water
  • acidic water

The functioning principle a water ioniser is based on is called electrolysis. What’s? electrolysis? Electrolysis is the process of decomposing water into the basic components hydrogen and oxygen by applying electric power.

In terms of a water ioniser for producing drinking water, it splits the water molecule into hydrogen ion (H+) and hydroxyl ion (OH-). The level of electric power being applied allows the machine to change the hydrogen to hydroxyl ratio, thus controlling the PH of the water.

In the image below you can see the basic design of the structure of a water ioniser. It consists of two chambers separated by a membrane. In one of the chambers, we have the negative electrode and in the other, the positive electrode. Electric current is applied to the electrodes. When an electric current is applied, the positive ions are attracted to the negative electrode and the negative ions to the positive electrode.


Most of the supplied water pouring from the tap contains both alkaline and acid minerals. Before the water is supplied to the tap, the municipality is supposed to add acid minerals (sulphur, phosphorus, chlorine) to kill living organisms and microorganisms ensuring the water meets the required quality and safety standards. However, during the process, the water becomes too acidic and is not suitable for drinking. So, what they do further is to consequently add alkaline minerals (calcium, magnesium, sodium, potassium) to make the water non-acidic.

Hence, during the process of re-alkalization water does not become alkaline. The role of the alkaline minerals is to counteract the negative effects of the acids. As a result, the PH of the tap water becomes neutral.

Back to the scheme above, the negative electrode attracts the positive minerals (the alkaline minerals) whereas the positive electrode attracts the negative minerals (the acid minerals).

Most of the commercial water ionisers on the market are more complex and include additional systems to deal with positive and negative ions based on their nature. Thus, they can produce very high or very low PH water – for cleaning, watering flowers and plants or for other sanitation purposes.

Do you have any questions? Please ask.