How much sodium does a Water Softener add to my water?

For every grain of hardness in your water, 7.5 mg of Sodium will be added to each litre of water by the ion-exchange method. For example, if you have water that is 10 grains per gallon hard; you will add 75.0 mg of Sodium per quart of water softened by ion-exchange. To put that in perspective, one 8 oz glass of milk contains 120 mg of Sodium, one slice of white bread contains 114 mg of Sodium.