tap water

How Much Calcium Does Bottled Water Have? Water containing calcium carbonate at concentrations below 60 mg/l is generally considered as soft; 60–120 mg/l, moderately hard; 120–180 mg/l, hard; and more than 180 mg/l, very hard (McGowan, 2000). Which bottled water has the least calcium? 1. Aquafina. Like most of the entries on the low-calcium list,