Softening hard water can mitigate many of its objectionable effects. Water softening can be done either at point of entry or point of use. One of the unique advantages offered by point-of-use water softening is the opportunity for homemakers to have either hard or soft water for drinking. This choice is not available if the water supply is softened municipally. Hardness minerals can be reduced in water to make it “softer” by using one of three basic means:
Chemical softening—lime softening, hot and cold; lime-soda softening
Membrane separation softening—Nano filtration
Cation exchange softening—inorganic, carbonaceous, or organic base exchangers
Softening water for home needs is done almost exclusively through the use of cation exchange.