What type of water encourages the formation of soap scum due to its high mineral content?

Hard water is characterized by a high mineral content, primarily calcium and magnesium ions. When soap is used with hard water, it reacts with these minerals to form an insoluble substance known as soap scum. This scum is what causes the soap to be less effective and can leave residues on skin, dishes, and surfaces.

In contrast, soft water has been treated to remove these minerals, which prevents the formation of soap scum. Distilled water is also free of minerals, produced by boiling water and condensing the steam to remove impurities. Tap water can vary but may contain some minerals; however, it is often treated to keep hardness levels moderate, reducing the likelihood of significant soap scum formation compared to hard water. Therefore, the high mineral content found in hard water directly contributes to the issue of soap scum.