Depending on where you live, there’s a good chance that the water flowing through your faucets started out as groundwater. Groundwater accounts for more than one third of the drinking water used in the United States1. What starts as rain or snow travels into the ground through cracks and crevices in sand, soil and stone, and the material that it travels through has a big impact on its quality. When rainwater flows through porous rocks like limestone or dolomite it picks up and dissolves the minerals hidden within, while water that flows through glaciers or less permeable rocks remain relatively free of dissolved materials. Ground water that contains a high concentration of minerals is considered hard — it has a reputation for building up in pipes and leaving a film on glassware. Soft water leaves pipes pristine, provides luxurious lather when you’re washing your hands, and leaves your skin feeling softer after you bathe. But one of the most important differences between the two lies in what they do – or don’t do - for your health.
When we think about what’s in our water, we tend to look first for what is harmful - what shouldn’t be there (and needs to be filtered out). This has been an issue for consumers and scientists alike. In fact, following their initial report identifying substances in the water supply that might pose risks to public health, the Safe Drinking Water Committee realized that their study had neglected the positive aspects of public drinking water. They conducted a second examination2 to identify nutrients necessary for optimal health in drinking water. The group highlighted calcium and magnesium as being of particular interest in hard water areas because their high concentration made them a major contributor to achieving recommended daily allowance levels. And another study conducted by the USDA’s Nutrient Data Laboratory for the same purpose identified the same minerals present in public water in quantities representing more than 1% of the U.S. Daily Value (DV)4
Water that is considered soft generally contains less than 60 parts-per-million (ppm) of calcium and magnesium and water that is hard has more than 120 ppm.3 The nutritional study revealed that the average concentration of calcium in public water supplies contributed about 6.5 percent of the RDA, and approximately 36% in hard water areas. For magnesium the average concentrations in public water supplies provided between 3% and 7% of the RDA, while in hard water areas the nutritional benefit was over 50% of the RDA.
The consensus from these studies is that there are real benefits provided by the presence of these minerals in water, and that in some cases their concentration levels are high enough to make up for nutritional deficiencies or to offer health advantages to those who drink at least two liters of water a day.
- Calcium is the backbone of healthy growth and bone development, but over 50% of North Americans do not take in enough of it to prevent osteoporosis and fractures.
- Magnesium consumption can prevent cardiovascular disease, but the National Institute of Health estimates that 48% of Americans take in less than their Estimated Average Requirement.
In 2004, the World Health Organization published an extensive study that detailed the health risks of drinking demineralized water, concluding that:
Sufficient evidence is now available to confirm the health consequences from drinking water deficient in calcium or magnesium. Many studies show that higher water magnesium is related to decreased risks for Cardiovascular Disease and especially for sudden death from Cardiovascular Disease. ….. Recent studies suggest that the intake of soft water, i.e., water low in calcium, is associated with a higher risk of fracture in children, certain neurodegenerative diseases, pre-term birth and low weight at birth and some types of cancer. Furthermore, the possible role of water calcium in the development of Cardiovascular Disease cannot be excluded.5
The full benefits of minerals present in tap water are considerable: Low magnesium levels in those with type 2 diabetes can be offset through drinking water with average to high magnesium levels, and calcium concentrations increase in vegetables cooked in hard water.6
Mineral-rich tap water offers nutritional benefits beyond hydration, but that doesn’t negate the need to filter out harmful contaminants. The Aquagear filter is designed to remove unwanted tap water contaminants while preserving the healthy minerals like calcium, magnesium, and potassium in your water.
- The Quality of the Nation’s Groundwater. Retrieved from The U.S. Geological Survey. (2015)
- The Contribution of Drinking Water to Mineral Nutrition in Humans. Retrieved from the National Research Council Safe Drinking Water Committee. (1980)
- Is Hard Water Dangerous to Drink? Retrieved from the McGill University Office for Science and Society. (2019)
- The Mineral Content of U.S. Drinking and Municipal Water. Retrieved from the USDA.gov. (ND)
- HealthRisks from Drinking Demineralised Water. Retrieved from the World Health Organization website. (2004)
- Changes in the Mineral Composition of Food as a Result of Cooking in “Hard” and “Soft” Waters. Retrieved from the Archives of Environmental Health. (1981)