Water Softeners and Your Health
Investigating the Health Consequences of Water Softeners
Do Water Softeners Pose Health Dangers?
The water softening process using salt-based systems depends on ion exchange or displacement, which is a reversible reaction. During this process, calcium (Ca2+) and magnesium (Mg2+) ions in hard water are replaced by sodium ions (Na+), which are released from the ion-exchange resin into the water. Simultaneously, the calcium and magnesium ions bond to the resin. Essentially, ion swapping occurs: sodium ions transition from the resin to the water, while calcium and magnesium ions shift from the water to the resin. It’s crucial to recognize that the resin matrix remains unchanged throughout the softening process. When the sodium ions in the resin matrix are entirely substituted by calcium and magnesium ions, the resin becomes saturated and can no longer soften water, necessitating regeneration. Regeneration involves introducing salt (sodium chloride) to the chamber, which displaces calcium and magnesium ions with sodium ions, restoring the resin’s ability to soften hard water. For most healthy individuals, the extra sodium in softened water doesn’t pose health risks. However, for individuals with hypertension on low-sodium diets, the sodium in softened water can be harmful.
Is Health Adversely Affected by Water Softening?
Water softeners do introduce sodium into drinking water, sparking health risk concerns. The water softening industry, however, has dismissed the idea that sodium addition during softening leads to adverse health effects. The Water Quality Association (WQA), an international non-profit representing the water treatment industry, has declared that ion exchange water softening doesn’t lead to health issues. Chloride ions don’t stay in the water; they simply pass through the resin bed during regeneration and are discarded with the waste as calcium chloride and magnesium chloride. Sodium ions are introduced to the softened water in tiny amounts, replacing the calcium and magnesium ions removed. For example, removing 1 mg/L of calcium carbonate water hardness results in only 0.46 mg/L of sodium addition. Even water with a total hardness over 1200 mg/L would still be considered a “Low Sodium” beverage by the U.S. Food and Drug Administration due to the minimal amount of added sodium.
Is the Sodium Content in Softened Water a Health Concern?
Water softeners add sodium to tap water, making it a concern for individuals with hypertension who are on low-sodium diets. According to Mayo Clinic experts, the amount of sodium added by softeners depends on the water’s hardness. Although reducing sodium intake is most effective by minimizing processed foods and table salt, monitoring sodium levels in drinking water is also important. Mayo Clinic physicians suggest that individuals find out their tap water’s hardness from their local water authority and then calculate the sodium added to their softened water. This is done by multiplying the water’s hardness (in grains per gallon) by 8 (or 7.866 for accuracy), then adding this to the sodium naturally present in municipal tap water to get the total sodium content. For well water, an estimated average sodium addition can be calculated based on a hardness of 278 mg/L, though this can vary. The harder the water, the higher the sodium content is likely to be.
Studies in the Archives of Internal Medicine suggest that sodium levels in softened water can differ based on the water’s hardness. Research in the Journal of the American Dietetic Association indicates that Americans commonly consume more sodium than needed for physiological functions, and the sodium contribution from drinking water might be overlooked. It’s estimated that water contributes to about 10% of a person’s daily sodium intake, highlighting the importance of being aware of one’s water supply’s sodium content. For those on sodium-restricted diets, it’s recommended to avoid softened water or tap water with high sodium levels (approximately 42% of U.S. water supplies contain excessive sodium). Instead, they should choose purified, filtered water. Bottled water may not be sodium-free, as around 25% of it is merely tap water labeled as “spring water.” Individuals are advised to purify their water at home using reverse-osmosis systems to ensure they are aware of their water’s content. For those with hypertension or sodium-related concerns, filtered, purified water is the best option.
Substituting Potassium for Sodium in Water Softening
While the water softener industry argues that the sodium added during softening is insignificant and not a health issue, medical professionals and consumer groups have pushed for potassium-based water softening alternatives. This alternative isn’t widely used yet due to the higher cost of potassium chloride (KCl) compared to sodium chloride (NaCl), which can be three to four times more expensive.