How Do Water Softeners Work?

Most water softeners work due to the ions within the systems – as water passes through the water softener, the ions that make water hard are exchanged for other ions and water is therefore softened. Depending on the type of water softener, this can result in water with a slightly higher salt content.

What is Hard Water?

Water hardness is mainly due to calcium (and sometimes magnesium) in the water supply. To soften the water an ‘ion-exchange’ softener removes the calcium and magnesium almost completely.

There are three main processes that take place within your water softener:

  • The softener contains tiny beads of ‘ion-exchange resin’.
  • These beads of resin are preloaded with sodium and as the water passes through the beads, the calcium and magnesium in the water supply swap places with the sodium.
  • Calcium and magnesium remain on the resin, while sodium goes into the softened water. As sodium does not cause hardness, the water becomes softened

What Causes Hard Water?

The quality of your water, and whether it is hard or soft, is determined by the geology of the ground in your region. Pure rainwater is naturally soft, but the chalk and limestone regions of the south and east of England deposit calcium and magnesium into the natural water supply as rainwater passes through the rocks, which results in hard water.

The granite areas of the north and west do not contain the same minerals and so the water remains soft. With the development of water distribution networks, some parts of the UK which have historically been soft water areas are now beginning to experience hard water.

Check how hard your water is with our ‘Water hardness map’.




For more information or for a Free Home Survey

Call Capital Softeners on 01707 691 819
or email