I am currently living in my parents house, which is fed water by a private well. Due to the mineral content in most well water, we use a water softener. For those of you with city water, a water softener is a type of ion exchange filter which uses salt (sodium chloride) to replace calcium, magnesium, and other metals in the water with sodium. None of these minerals are hazardous, but they do stain everything, so reducing them is desirable.