dqb,

I presume that Javier fears that the brine that used to recharge the
resin tank may be too salty for the septic system. I don't think that's ever
been the case. He should check the size of his septic tank. As for the leach
field, the softened water that goes through the septic tank and the brine
both contain sodium chloride which may accumulate in the leach field. This
salt eventually gets washed away by rain. I guess it's possible during a
drought for enough salt to build up to stress the grass a bit. Never heard
of this though.

Dave M.