It depends on the hardness of your water, but on average less than 3% of your sodium intake comes from drinking softened water. It is estimated that the average person consumes the equivalent of two to three teaspoons of salt a day from various sources. Assuming a daily intake of 5 grams (5000 milligrams) of sodium in food and the consumption of three quarts of water (i.e., coffee, tea, fruit juices, and drinking water), the contribution of sodium (Na+) in the water from the home water softening process is minimal compared to the total daily intake of many sodium-rich foods. The formula for calculating the amount of additional sodium follows: mg of Na / quart of softened water = grains of hardness X 7.5 mg Na / grain of hardness.