Why do water softeners have to be loaded with sodium (salt)?

As the water softener goes through several cycles, the sodium in the beads is depleted. Water softeners thus lose the ability to soften water after a few cycles. To cure this problem, water softeners enter a regeneration cycle, during which the beads in the unit are soaked in a strong salt, or sodium chloride, and water solution.

The high amount of sodium in the solution used by water softeners during regeneration forces the magnesium and calcium ions attached to the beads to give way and the beads are subsequently recharged with the sodium. The brine, including the minerals, is then flushed through a drainpipe by the water softener. Regeneration cycles of water softeners create around 25 gallons, or 95 liters, of salty water.

The majority of water softeners use this salt and plastic bead approach. Water softeners mainly vary in the way the regeneration process is activated. Some water softeners use electric timers, which will regenerate and flush water softeners at pre-scheduled intervals. Others use computers to judge the depletion of beads in accordance with the amount of water used.

Another variety uses mechanical meters to measure the use of water and activate regeneration only when it is required by sodium depletion.
Each one of these water softeners has its advantages and disadvantages. Systems with electric timers will usually not dispense water while in the regeneration cycle. Water softeners using computers may provide a little water during this cycle as a result of having a small resin reserve.

Softening systems using the mechanical system usually have two tanks, making them the most flexible of the water softeners available at present. Water softeners can cost between $400 and as much as $2,700, depending on type and make. As a rule, they are fairly easy to install, as well as remove. Plumbers will install water softeners for between $100 and $600, but some stores selling water softeners offer free installation.