Water Q&A: Why can't I rinse the soap off my hands?

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Learn how "soft water" and "hard water" can affect how soap works.

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Why can't I rinse the soap off my hands?

Water Questions and Answers

The terms "soft water" and "hard water" are important here. Water is said to be hard whem it has a high concentration of calcium and magnesium ions. In soft water, there are concentrations of sodium and postassium ions.

If you use hard water, then it is harder to get soap to lather up as you wash. You might end up having to use more soap in this case, as opposed to using soap with softer water. When you use hard water, you feel like you are easily rinsing off the soap from your hair and skin - your skin may feel "squeaky clean"! Yet, with hard water, there is still a slight film of insoluble soap curd on your skin (and on the shower walls and glass doors). Soap curd on hair may make it dull, lifeless and difficult to manage. Most people have hard water so this what what they are used to.

Ironically, when using soft water, your skin has that slippery feeling even after extensive rinsing. You might think you cannot rinse off all the soap on your skin, but actually you are cleaner than if you used hard water! You are feeling hydrated skin, not skin with a soapy residue.

Soft water leaves less of a residue not only in the shower but also in the kitchen, as in your dish washer and on your dishes and glasses. Hard water can leave a film or spots on glasses taken out of the automatic dishwasher and can contribute to calcium buildup (scale) inside of water pipes. Hard water can even shorten the life of fabrics and clothes. Hard water is prevalent in some parts of the country, and sometimes water-softening chemicals that reduce the amount of calcium and magnesium are added to the water.