Activated charcoal can be added (and changed out from time to time) at the top of the bead media in home water softener systems of certain brands. In a properly designed system the softened water then goes thru the reverse osmosis filter. Kinetico was the top brand of home system a few years ago, not sure now.
P.S. they are trying to kill us all, since the system cannot keep paying geezers living to 90 and beyond drawing Social inSecurity.