This document discusses hard water, the causes of hard water including calcium and magnesium ions naturally occurring in soil, how hard water affects homes with decreased soap lathering and increased lime scale, and the two main types of water softening systems - salt-based systems that are most effective but require salt replenishment and saltless systems that are less effective but don't use salt. It recommends reading reviews, considering local restrictions, and seeking professional advice when selecting an appropriate water softening system.