Calcium in Drinking Water: Health Benefits & Optimal Levels

Overview of Calcium in Drinking Water

• What it is: Calcium (Ca) is an essential mineral and the primary contributor to water hardness. It's the most abundant mineral in the human body, crucial for biological functions far beyond bone health.
• Why it matters: Drinking water can contribute 5–20% of daily calcium intake. Studies link calcium-rich water to better bone density, lower cardiovascular risk, and reduced kidney stone formation (contrary to old myths).
• Natural sources: Calcium dissolves from limestone, chalk, marble, and gite deposits. Hard water regions—like the Mediterranean, Alps, and limestone aquifers—naturally have higher calcium content.
• Optimal range (40–80 mg/L): This range provides meaningful nutritional benefit without excessive hardness. Water tastes clean with a subtle mineral character. Premium mineral waters often target this range.
• Too high (>150 mg/L): Creates very hard water that leaves scale deposits on fixtures, reduces soap effectiveness, and can give water a chalky taste. May stress kidneys in sensitive individuals.
• Too low (<20 mg/L): Soft water lacks the cardioprotective benefits of calcium. Some studies suggest very soft water may increase cardiovascular risk. Tastes "empty" to those accustomed to mineral water.