Soft water - what is it?

What qualities soft water has, whether it is suitable for drinking, and where soft water occurs naturally, can be read in this article.

Properties of soft water

Soft water has a water hardness of zero or nearly zero.

This is because no hardeners are dissolved in it, or these hardeners were previously removed. Hardness builders are:

  • calcium
  • magnesium
  • strontium

Strontium, which occurs only in very small amounts in nature, but plays as a hardness-forming but hardly a role.

The equilibrium between calcium and magnesium, however, is constant in almost all naturally occurring waters and is compensated by the content of carbon dioxide in the water.

Due to the lack of hardeners, depending on the other mineralization of the water, the pH may be slightly lower (around 5 to 6) and the water may therefore have slight acid properties. It also contributes to the corrosion of pipes and reacts aggressively.

Similar properties are also observed in distilled water and osmosis water.


Rainwater is naturally soft water. It is caused by the rising and condensation of water vapor and is virtually distilled water before it reaches Earth. Since it can not dissolve calcium or magnesium ions on the way down, which only occur in the soil, it remains soft water.

Osmosis water and distilled water

Osmosis water and distilled water are free of all ions and salts. This also applies to demineralised water. They also belong to the soft water category.

Advantages of soft water

A lower degree of hardness means that the water usually has a better cleaning performance than harder water. But that depends on the other dissolved ions and minerals. The fewer minerals are dissolved in the water, the lower the pH is usually.

Softer water also means less detergent consumption and less likely to cause skin irritation than too hard water.

Lower water hardness also results in less deposits in equipment where water is heated. Lime margins and lime spots are also less likely to form.

Disadvantages of soft water

It can be aggressive, and so increase the corrosion of pipes. In addition, soft water dissolves soap worse than hard water.

Tips & Tricks

Water softening systems only make sense if the water is classified as "hard". This is in Germany from a water hardness of 14° dH.

Video Board: Hard vs. Soft Water: What's The Difference?