The amount of salt in softened water depends on how hard the water is to start with. The amount is very small, compared to the amounts that would be bad for you, even in extreme hard water areas. I've seen estimates of around 100mg of sodium/litre of softened water, compared to around 10mg/litre of sodium in the water before passing through the water softener. So, a typical intake of 2 litres of water per day equates to around 200mg sodium. The recommended daily sodium intake is around 2500mg, most of it coming from food. Bear in mind also, that too little sodium is bad for you, causing hyponatraemia, characterised by things like convulsions and cardiac arrhythmias.
