Demineralization is the process of purging all ions in the water. Positive ions in the water are caught with cation exchange tank, and negative ones with anion exchange tank. Ion exchange resins are used in cation and anion exchangers. With these two units, the conductivity of the water can be decreased to very low levels.

The conductivity of water is decreased to very low levels with these systems especially in industrial fields such as power plants and woodworking facilities where low conductivity is favored.