Process:
NaCl (=Salt) reacts with the lime dissolved in water and is divided into Na (=Sodium) and Cl (=Chloride):

Na (=Sodium) is released into the de-mineralised drinking water and represents a further loading material for the organism (the legal limit in Southern Germany is: 150 mg sodium / l).

Cl (=Chloride) reacts with lime and becomes to the even harder Calcium-Chloride:
This way, the problem of the hardening ions (calcium and magnesium) is aggravated and shifted back into the sewer and, therefore, into the purification plants.
For this reason water softening devices based upon ion-exchange (with salt) are no longer approved in regions with high levels of water hardness (i.e. those with much lime).

Conclusion:
A not recommendable solution for water softening which is recognized meanwhile even by authorities