When a water softener reaches its softening capacity it needs to perform an automated cleaning procedure to regenerate its softening resin. This process involves adequately cleaning the softening resin with saturated salt and then thoroughly rinsing it with clean water before placing the water softener back into softening mode.
Any water used to clean the water softener during this process is sent directly to drain so sizing your system correctly will help minimize water waste. Ideally your water softener should be sized to regenerate no more than once a week but this figure may vary depending on your specific needs.
A water softener usually uses slightly more salt than is necessary for every regeneration cycle, this is normal and is the only way to ensure that the softening resin is adequately regenerated. The amount of salt wasted is usually very small but as you can see, a system which cleans less often wastes less salt, therefore increasing salt efficiency.
Water softeners are static filtering devices meaning that there are usually no major moving or wearing parts during the filtration process. The only time a water softener encounters mechanical wear and tear is during the regeneration cycle. This process requires the water softener to do a number of functions correctly and over time the parts required for this process will begin to wear, thus requiring replacement.
A correctly water softener will last longer and give less trouble than an undersized water softener. As an example, two water softeners are working side by side, the first water softener regenerates once per week and the second water softener regenerates twice per week. The first water softener will encounter half the wear and should last twice as long as the second water softener.