I have a built-in water softening system. For some reason, this involves buying vast quantities of salt every few months and tipping it by the bag into the mysterious machine.
It seems a lot of trouble for having drinkable tapwater, but there you are. The wife seems to like it.
Salt is bad for you all the same, as we repeatedly seem to be told.
I think the stuff that comes out of the blue tap has got the salt in and we just use that for washing, etc. The stuff that comes out of the green tap is all filtered and whatnot.