Soft water often raises questions about its sodium content, especially for those mindful of dietary intake. While water softeners effectively remove hardness-causing minerals, they introduce a small amount of sodium. This article clarifies typical sodium levels in softened water, explores its health implications, and discusses practical ways to manage it.
Understanding Water Softening
Water softening addresses “hard” water, which contains elevated levels of dissolved minerals, particularly calcium and magnesium. These minerals can lead to scale buildup in pipes and appliances, reduce soap lathering, and leave residues. Most residential water softeners use an ion-exchange process.
During ion exchange, hard water passes through a resin bed charged with sodium ions. As calcium and magnesium ions from the hard water contact these beads, they exchange places with the sodium ions. This chemical swap removes hardness minerals, replacing them with sodium to create soft water.
Quantifying Sodium in Softened Water
The amount of sodium added to water by a softener directly correlates with the initial hardness of the water. The harder the untreated water, the more sodium is introduced. For every grain per gallon (gpg) of hardness removed, approximately 1.89 to 2 milligrams (mg) of sodium are added to an 8-ounce glass of water. Other estimates suggest about 7.5 mg of sodium per liter for every grain of hardness.
For example, if your water has 10 grains of hardness, an 8-ounce glass of softened water would contain about 18.9 to 20 mg of added sodium. A typical slice of white bread, in comparison, contains around 114 to 170 mg of sodium, and an 8-ounce glass of milk has about 120 mg. This illustrates that the sodium contribution from softened water is often modest compared to common dietary sources.
Health Considerations
For most healthy individuals, the amount of sodium added to water through softening is not a significant health concern. The majority of daily sodium intake comes from food, particularly processed items and table salt.
However, individuals on sodium-restricted diets, such as those managing high blood pressure or kidney disease, should consider this additional sodium. While the contribution is generally small, it can become a factor for those requiring strict sodium limitations. In such cases, consulting a healthcare professional for personalized advice is recommended.
Minimizing Sodium from Softened Water
For individuals concerned about the sodium content in softened water, several practical solutions exist. One common approach is to install a bypass line that provides unsoftened water to a specific tap, typically in the kitchen, for drinking and cooking. This ensures that only water used for bathing, laundry, and dishwashing is softened, while potable water remains untreated.
Another effective method is to install a reverse osmosis (RO) system. These systems are highly efficient at removing dissolved solids, including sodium, from water. An RO system can eliminate 95-99% of sodium, making it a suitable option for those on low-sodium diets or who prefer to minimize their intake. RO units are often installed under the kitchen sink, providing a dedicated source of purified drinking water.
Additionally, some water softeners can use potassium chloride instead of sodium chloride for regeneration. Potassium chloride introduces potassium ions into the water instead of sodium ions, which may be preferable for certain health considerations. However, potassium chloride is typically more expensive and may be less efficient, potentially requiring more frequent regeneration or higher quantities of the product.