The Delta Hydro@Home water softeners work on the basis of ion exchange. This is done with the help of resins, which retain the dissolved hardness minerals (calcium and magnesium) and so removes them from the water.

In the water softener, the tap water is sent through a resin tank, where the calcium and magnesium ions in the water (which cause the limescale deposit) are replaced by harmless sodium ions. This process is called ion exchange. When the resin is saturated with limescale ions, it is renewed again and again by rinsing the resin column with a brine solution. Through the same process of ion exchange, the stored calcium and magnesium is flushed to the drain. This process is called regeneration and is done automatically by the device.