Dissolved minerals, such as calcium and magnesium compounds, make water hard, affecting the taste and feel of water, reducing the efficiency and longevity of plumbing fixtures and rendering soaps and detergents less effective.
To remove these impurities, the most common method involves passing the water through a water softening unit. The water softener includes a resin tank that is filled with a bed of resin beads and a brine tank that holds a salt solution.
In a process known as an “ion exchange,” the positively charged calcium and magnesium ions in the hard water pass through the resin bed and exchange places with positively charged sodium ions that are on the beads. This leaves water that is “softer,” meaning the impurities have been removed.