As we speak, hardness minerals (such as calcium and magnesium) are slowly building up in your home on everything your water touches. This includes things like your water heater, your dishwasher, your faucets, and even your skin.
It doesn’t matter if your water is from a well, or the city supply, most homes in the US have hard water. Few people know, but you can only remove hard minerals from your water through ion exchange, which is what a water softener does.