Water softeners are common appliances in homes with hard water, designed to protect plumbing and appliances from mineral buildup. These systems remove high concentrations of dissolved minerals, primarily calcium and magnesium. Because the softening process involves a chemical exchange, it introduces a small amount of sodium. For the majority of healthy adults, this minimal sodium increase poses no health risk, but understanding the mechanics of this process is necessary to address specific dietary concerns.
How Water Softeners Change Water Composition
The process that removes hardness minerals is called ion exchange, which forms the basis of traditional water softeners. Hard water flows through a tank containing a bed of small resin beads that are coated with sodium ions. As the water passes over these beads, the positively charged calcium and magnesium ions are chemically attracted to the resin and held there. The resin releases a proportional number of sodium ions into the water in exchange for every calcium or magnesium ion it captures, which removes the minerals that cause scale and soap scum. The amount of sodium added to the water is directly determined by the initial hardness level of the raw water supply.
Assessing the Sodium Intake from Softened Water
The small amount of sodium added during softening is generally insignificant when viewed in the context of an average person’s diet. For water with a typical hardness level, an eight-ounce glass of softened water may contain only around 12 to 28 milligrams of sodium. To put this into perspective, a single slice of white bread often contains around 170 milligrams of sodium, and a cup of milk can contain over 120 milligrams.
For most healthy individuals, the sodium contribution from drinking softened water is negligible and accounts for a very small fraction of the recommended daily intake. The added sodium does not make the water taste noticeably salty, except possibly in cases of extremely hard water. Water is still considered safe to drink when its sodium content is below 200 milligrams per liter, a level only exceeded when the raw water is exceptionally hard.
Caution is necessary, however, for specific populations where even a slight increase in sodium intake is a concern. Individuals on a severely sodium-restricted diet, often prescribed for conditions like hypertension, kidney disease, or heart failure, should consult a doctor about their water consumption. In these medically sensitive cases, the cumulative intake of sodium from water throughout the day could become relevant to their health management.
Another group that requires special consideration is infants, particularly when preparing formula for babies under six weeks old. Infant formula is precisely balanced for sodium content, and the added sodium from softened water can upset this balance due to an infant’s underdeveloped kidneys. Using unsoftened water for formula preparation is usually the recommended course of action.
Drinking Water Alternatives and Solutions
Homeowners who use a water softener but are concerned about the sodium content have several practical options for their drinking water supply.
Bypass Line Installation
The simplest solution is to install a bypass line during the softener installation, leaving the cold water tap in the kitchen unsoftened. This allows the rest of the house to benefit from soft water while providing a separate source of untreated water for drinking and cooking.
Reverse Osmosis (RO) Systems
Another effective solution is the installation of a point-of-use reverse osmosis (RO) system, typically placed under the kitchen sink. An RO system uses a semi-permeable membrane that filters out nearly all dissolved solids, including the sodium added by the water softener. This process results in highly purified drinking water that is virtually free of sodium and other contaminants.
Potassium Chloride Regeneration
For those who want to soften their water without introducing sodium, some systems can be regenerated using potassium chloride instead of sodium chloride. Potassium chloride swaps the hardness minerals for potassium ions. However, this alternative is often more expensive and may not be as efficient in softening the water compared to the traditional sodium chloride method.