Hundreds of active and healthy centenarians live in the Nicoya Peninsula of Costa Rica. This is one of the world's biggest "blue zones", where a large percentage of people enjoy remarkably long lives. Dr. Mehmet Oz, who has studied the lifestyle of these long-lived people, attributes their longevity to their physical activity and the fact that they drink hard water, i.e., water high in calcium and magnesium which helps to maintain strong bones.
By contrast, it is estimated that approximately 28 million people (1 in 9 or 10.29%) in the United States have osteoporosis and an additional 18 million have low bone mass. Many of these cases could be caused because the drinking water is too pure and does not have enough minerals to maintain equilibrium of the mineral ions in the bones. The situation is aggravated by the use of domestic chemical water softeners which substantially reduce the content of calcium in drinking water.
Calcium equilibrium was described by Professor B.E.C. Nordin in an editorial in the American Journal of Clinical Nutrition:
Calcium intake, absorption, and excretion make up the 3 components of the calcium paradigm. To remain in calcium balance, net absorbed calcium (the difference between dietary intake and fecal output) has to equal calcium losses in the urine and through the skin. If that is not achieved, the calcium balance becomes negative and the difference between intake and output is drawn from the skeleton to maintain the (ionized) calcium in the extracellular fluid. Sooner or later, probably in a matter of days, this requires bone breakdown and the development of osteoporosis.
Calcium (Ca++) intake is important at all ages, but the need is higher during childhood, fetal growth, pregnancy, and lactation. Epidemiological, animal, and clinical studies show that the occurrence of osteoporosis decreases as the dietary calcium intake increases. A diet that is fortified in calcium may reduce the rate of age-related bone loss and hip fractures, especially among adult women. In spite of this knowledge, nutritional surveys indicate that more than half of North Americans consume inadequate levels of calcium and, on average, adult women consume only 60% of the required daily calcium intake. Many foods, such as orange juice, are now fortified with calcium, but naturally bioavailable calcium is found almost exclusively in milk, milk products, and water. Drinking water may be a significant source of calcium, and calcium-rich mineral water may provide over one-third of the recommended dietary intake of this mineral in adults.
Epidemiological studies also suggest that increased dietary intake of magnesium (Mg++) reduces the occurrence of schemic heart disease, cardiac arrhythmias, and sudden death. Increased levels of magnesium in drinking water are associated with decreased occurrence of cardiac disease. The majority of the U.S. population consumes less than the daily magnesium requirement, and many individuals ingest less than 80% of the recommended level. Magnesium is found in foods such as nuts, green leafy vegetables, cereals, and seafood. However, magnesium in water is highly bioavailable, and is absorbed approximately 30% faster and better than magnesium from food.
NOTE: Calcium Chloride should not be combined with the bicarbonates because calcium carbonate precipitates. The sodium bicarbonate becomes sodium chloride (table salt), and potassium bicarbonate becomes potassium chloride.
Ca++ + 2 HCO3- → CaCO3 + H2CO3
H2CO3 → H2O + CO2
Measure carefully. Make sure that the spoons are level and not heaping. If you cannot find a measuring spoon set with 1/8 teaspoon, you can double the recipe. Use two liters of water and the more common 1/4 teaspoon measure. It is advisable to filter the source tap water with a water filter pitcher to assure that the water does not have heavy metals such as lead. Mix all the ingredients until the mineral salts are completely dissolved.
The bicarbonates make the water alkaline and can increase the pH of body fluids. The molecular weight of these compounds can be used to calculate the amount of each mineral in the recipe.Molar mass of CaCl2 = 110.984 g/mol (36.112% Ca by weight)
Since 1/8 tsp of each ingredient weighs approximately 0.6 grams (600 mg), the amount of each mineral can be calculated by multiplying the percentage by weight in the molar mass of the compound times the weight used in the recipe, e.g., 600mg × 0.27 for sodium. NOTE: The composition of home-made mineral water also depends on the minerals present in the water before addition of these mineral salts. Check with the water commission in your area to obtain an analysis of the minerals in your local water source. For example, the tap water in Washington, D.C.  has the following average concentrations of minerals in mg/L: Ca 38.9, Mg 10.3, Na 20.5, K 3.3.
For comparison, the table below lists the mineral compositions of several commercially available bottled waters in North America and in Europe. The mineral content of the Calcium/Magnesium water recipe above is similar to that of European waters with moderate mineral content, such as San Pellegrino from Italy. The European waters with a high mineral content are high in sodium and have a salty taste.
Many mineral waters are effervescent when they emerge from the ground. The fizzines is due to dissolved carbon dioxide (CO2) which forms bubbles as the water is decompressed from a high underground pressure to the atmospheric pressure on the surface. You can make your mineral water effervescent using a soda siphon and carbon dioxide cartridges like the ones illustrated here. Once you have prepared the mineral water recipe, pour it into the soda siphon, and plug in the carbon dioxide cartridge following the manufacturer's instructions. The soda siphon with the carbonated water may be kept in the refrigerator until ready for use.
Mineral Content of Some Commercially Available North American Bottled Waters (mg/L) 
|North American Waters||Ca++||Mg++||Na+|
|Adobe Springs, Calif||3||96||5|
|Black Mountain, Calif||25||1||8|
|Caddo Valley, Ark||36||3||2|
|Canadian Spring, Canada||11||3||2|
|Carolina Mountain, NC||6||0||5|
|Cobb Mountain, Calif||5||2||4|
|Crystal Geyser Alpine, Calif||0||6||13|
|Deer Park, Me||1||1||1|
|Georgia Mountain Water, Ga||2||0||0|
|Great Bear, NY||1||1||3|
|Hawaiian Springs, Hawaii||6||3||6|
|La Croix, Wis||37||22||4|
|Mount Olympus, Utah||8||2||3|
|Mountain Valley, Ark||68||8||3|
|Poland Spring, Me||0||2||3|
|Pure Hawaiian, Hawaii||0||0||0|
|Pure Spring Water, Ga||49||4||0|
|Talawanda Spring, Ohio||0||0||3|
|Talking Rain, Wash||2||2||0|
|A Santé, Calif||4||1||160|
|Canada Geese, Canada||282||10||36|
|Crystal Geyser, Calif||8||3||160|
|Lithia Springs, Ga||120||7||680|
|Vichy Springs, Calif||157||48||1095|
Mineral Content of Some Commercially Available European Bottled Waters (mg/L) 
|Low mineral content (less than 200 mg/L of Ca++, Mg++, Na+)|
|Abbey Well, United Kingdom||54||36||45|
|Acqua di Nepi, Italy||72||26||32|
|Acqua Fabia, Italy||124||5||15|
|Acqua Panna, Italy||15||5||3|
|Brecon Carreg, United Kingdom||48||17||6|
|Buxton, United Kingdom||55||19||24|
|Chiltern Hills, England||104||1||8|
|Crodo Lisiel, Italy||60||2||6|
|Font Vella, Spain||26||5||12|
|Glenpatrick Spring, Ireland||112||15||12|
|Highland Spring, United Kingdom||39||15||9|
|San Benedetto, Italy||43||25||8|
|San Bernardo, Italy||12||1||1|
|Spa Reine, Belgium||4||1||3|
|St. Michaelis, Germany||43||4||21|
|Strathmore, United Kingdom||60||15||46|
|Vichy Nouvelle, Finland||70||110||1|
|Vittel Bonne Source, France||91||20||7|
|Moderate mineral content|
(between 200 and 750 mg/L of Ca++, Mg++, Na+)
|Crodo Valle d'oro, Italy||510||51||2|
|Franken Brunnen, Germany||198||42||52|
|Hassia Sprudel, Germany||176||36||232|
|Vittel Hépar, France||575||118||13|
|Pedras Salgadas, Portugal||132||9||550|
|Salus Vidago, Spain||78||10||660|
|San Pellegrino, Italy||204||57||47|
|Vichy Original, Finland||100||110||220|
|Vittel Grande Source, France||202||36||3|
|High mineral content (more than 750 mg/L of Ca++, Mg++, Na+)|
|Kaiser Friedrich, Germany||5||4||1419|
|San Narciso, Spain||53||9||1120|
|Vichy Celestins, France||100||9||1200|
|Vichy Catalan, Spain||33||8||1133|