Bottled Water Contaminants
The water-softener industry has tried to diminish the claims of adverse health effects of sodium addition to tap water during the water-softening process. According to the industry group, Water Quality Association (WQA), an international nonprofit industry trade group representing residential, commercial, industrial, and small community water-treatment industry. WQA has said publicly the following:
There are no health problems caused by ion exchange water softening. The chloride ions are not added to the water. They merely pass through the resin bed during the regeneration cycle and are discharged with the regeneration waste as calcium chloride and magnesium chloride. Sodium ions are added to the softened water in place of the calcium and magnesium that has been removed---but at an inconsequential, minute rate. Each 1 mg/L of calcium carbonate water hardness removed adds only 0.46mg/L of sodium. Water with over 1200 mg/L of total water hardness would still be classified after ion exchange softening as a "Low Sodium" beverage by the U.S. Food and Drug Administration food labeling regulations because of the trivial amount of added sodium.
Sodium in Softened Water: Is It a Health Risk?
Water softeners do add sodium to the tap water. Hence, hypertensive people—that is, people with high blood pressure—who must take a low-sodium diet, should carefully watch the water they drink. According to physicians at the Mayo Clinic, the amount of sodium added to tap water by water softeners is dependent on the "hardness" (the amount of calcium Ca2+ and magnesium Mg2+ ions) of the water. Of course, doctors say that the most effective way to reduce one's sodium intake is to cut back on salty processed foods and table salt, as these two steps can drop one's systolic blood pressure by 2 to 8 millimeters of mercury (mm Hg). But it is also important to cut the sodium in one's water as well. In fact, the water one drinks can be an important contributor of sodium in one's diet.
The physicians at the Mayo Clinic suggested that people can find the hardness of their tap water from their municipal water authority or department and then use this information to determine the amount of sodium (milligrams per liter) added to their softened water, as follows:
- Inquire at the water department about the hardness of water in grains per gallon. "Grains" is a measure of "hardness," or calcium carbonate (CaCO3), per gallon.
- Multiply this hardness number by 8 (or 7.866 to be exact) to determine the amount of sodium added to water by a typical salt-based water-softening system. Some people try to make the calculation easy for the non-technical public by using a multiple of 7.5.
- Add this number to the sodium naturally occurring in the municipal tap water to obtain total sodium.