Softened water is treated to reduce its mineral content, primarily calcium and magnesium. These minerals cause “hardness,” leading to issues like scale buildup and reduced soap effectiveness. This process raises questions about the “salt” content in the treated water.
How Water Softeners Work
Water softeners operate on a principle called ion exchange. Hard water flows through resin beads saturated with sodium ions. As water passes, dissolved calcium and magnesium ions displace the sodium ions, binding to the negatively charged beads.
This exchange releases sodium ions into the water. This is a chemical exchange process, not a direct addition of table salt. Over time, resin beads become saturated with calcium and magnesium. To restore their effectiveness, the system undergoes a regeneration cycle. A concentrated brine solution, made from sodium chloride salt, flushes the resin. This forces bound calcium and magnesium off the beads, recharging the resin with sodium.
The Amount of Sodium Added
The amount of sodium added to water by a softener depends directly on the initial hardness of the water. Water hardness is often measured in grains per gallon (GPG). For every grain of hardness removed from the water, approximately 7.5 to 8 milligrams (mg) of sodium are typically added per liter.
To estimate the sodium content, one can multiply the water’s hardness in GPG by approximately 8 mg/L. For instance, if water has a hardness of 15 GPG, a liter of softened water would contain about 120 mg of added sodium (15 GPG x 8 mg/L). An 8-ounce glass of this water would contain roughly 28 milligrams of sodium. The total daily sodium intake from softened water will vary based on an individual’s water consumption and the specific hardness level of their untreated water.
Impact on Health and Taste
For most healthy individuals, the amount of sodium added to water by a softener is not significant and does not pose a health concern. To put this into perspective, an 8-ounce glass of milk contains approximately 120 milligrams of sodium, and a slice of white bread can have between 120 and 170 milligrams. The American Heart Association recommends a daily sodium intake of no more than 2,300 mg, with an ideal limit of 1,500 mg for adults, especially those aged 51 and older.
Softened water typically does not taste salty. The concentration of sodium added is usually too low to be perceptible to most palates. If softened water does taste salty, it often indicates a malfunction within the water softening system, such as a clogged line or an issue with the regeneration process, rather than a normal operational characteristic. Individuals on strict sodium-restricted diets should consult their doctor regarding their overall sodium intake, including that from softened water. For those with specific dietary concerns, options like installing a reverse osmosis system can further reduce sodium levels in drinking water.