What type of water contains minerals that reduce soap or shampoo lathering ability?

Hard water contains a high level of dissolved minerals, primarily calcium and magnesium ions. These minerals interact with soap or shampoo, forming insoluble compounds that inhibit the lathering ability of these products. When using hard water, the minerals react with the fatty acids in soaps to create a film that prevents proper lathering, which can result in less effective cleansing and can leave a residue on hair and skin. Therefore, individuals using hard water may notice that they need to use more shampoo than usual to achieve the same level of cleanliness and foam. This understanding is crucial for anyone in the hair care industry, as it affects product recommendations and hair management techniques for clients who may have issues with hard water.