Bottled water containing not less than 250 parts per million total dissolved solids may be labeled as mineral water. Mineral water is distinguished from other types of bottled water by its constant level and relative proportions of mineral and trace elements at the point of emergence from the source. No minerals can be added to this product. If the total dissolved solids (TDS) content of mineral water is below 500 ppm, or it is greater than 1,500 ppm, the statement "low mineral content" or "high mineral content," respectively, must appear on the principal display panel. If the TDS of mineral water is between 500 and 1,500 ppm, no additional statements are needed.

Marketing campaigns for commodity bottled waters try to make us think water must be "pure" to be good. Being clean and healthy isn’t enough - water has to be pure, and the purer the better. These marketers tell us that nothing but hydrogen and oxygen should be in our water. Ironically, this misconception means people often drink distilled water when taking mineral supplements, which contain the same minerals that have been removed from the water.

Even distillation, which removes more contaminants than any other purification method, does not produce completely "pure" water. Rising steam is supposed to leave all impurities behind in the distilling process, but in fact gases, some chemicals, and some organic compounds can be taken along with the steam. Active carbon filters are used to eliminate those remaining contaminants from distilled water, but some impurity remains with this process, too.

In reverse osmosis (RO), water molecules are forced through a rubber membrane, leaving impurities behind. But gases, some chemicals (including chloramine and arsenic), and some bacteria can beat this technique, too.

So there is no such thing as pure water. It’s a myth. Natural water has mineral content. By removing minerals, water becomes acidic and aggressive, meaning it will seek to replace the minerals removed. Water treated by either distillation or RO will become acidic upon contact with air airborne carbon dioxide reacts with the water, taking the place of the removed minerals or contaminants.

Because water is a universal solvent, rainwater collects particles and chemicals even as it’s falling. Geological strata only add more to the composition the minerals and trace elements of the local area give each water its distinct terroir. Underground geology may filter water for decades or even millennia; when the water finally emerges at the source, it may not be "pure," but it is nevertheless clean and healthy. Clean, healthy water does not have to be pure. In fact, the waters with the most epicurean interest contain minerals and trace elements.

Magnesium - Mg++

Almost all human cells have some level of magnesium in them, and adults need three to four hundred milligrams of magnesium every day. Magnesium is important for the regulation of muscle contractions and the transmission of nerve impulses, and it activates energy-producing enzymes. Bone structure also relies on magnesium, and it expands blood vessels, which lessens the risk of heart attack. Nervousness, lack of concentration, dizziness, and headaches or migraines may result from magnesium deficiency. Most bottled waters have below 20 mg/l of magnesium, though some may have as much as 1000 mg/l.

Calcium - Ca++

Adults need about eight hundred milligrams of calcium per day--babies don’t require as much, but fifteen to nineteen year olds need significantly more. The many benefits of calcium include It stabilizing bone structure, teeth, and cell membranes; ensuring nerve and muscle impulses are properly transmitted; and helping to prevent blood clotting. Calcium also has a balancing effect for numerous skin allergies. Bones decalcify (osteoporosis) and fractures become more likely if a body is not getting enough calcium. Bottled water usually has less than 100 mg/l of calcium, but a few examples have about 500 mg/l.

Potassium - K+

Two to four grams is usually a sufficient day’s supply of potassium. Children and young people should pay particular attention to their intake, since potassium aides the growth of cells. The pressure of water between cells is regulated by potassium, which also makes sure each cell gets enough food. Potassium has special roles to play in muscle contraction and the formation and conduction of impulses of the heart. Potassium deficiency can weaken skeletal muscles and make smooth muscles tired. Typical potassium content in bottled water is less than 5 mg/l, but some (such as Ferrarelle and Malvella) can have as much as 50 mg/l.

Sodium - Na+

A person’s level of exertion largely determines his or her daily requirement of sodium. Normally about three grams are necessary, but severe physical stress can bring the requirement up to fifteen grams or more. The heart’s metabolism is affected by sodium, as is the regular contraction of the heart. Today, we rarely have to worry about sodium deficiency: Salt is an integral part of many foods, especially those that are highly processed. Sodium in bottled water ranges from 10 mg/l in most bottled waters to 1,200 mg/l in a few waters, such as Vichy Catalan and Vichy Célestins.

Sulfate - SO4-

Sulfates are the salts of sulfur. They aid the liver in detoxification and help digestion by stimulating the gall bladder. Sulfates in high doses act as a laxative. Fish, meat, and milk contain sulfates, which are an important component of protein. The human body only absorbs small amounts of sulfates, but these amounts are sufficient to stimulate peristalsis by binding magnesium and sodium to water in the intestine. This effect makes mineral waters rich in sulfates, which taste slightly bitter, suitable as “nonalcoholic bitters” after a meal. Most bottled waters have well below 100 mg/l of sulfates, but San Pellegrino and a few others can reach 500 mg/l.

Bicarbonate - HCO3-

Present in all biological fluids, bicarbonate is essential for maintaining our bodies’ pH balance. The substance is also found in stomach secretions. Lactic acid generated by physical activity is neutralized by bicarbonate dissolved in water; a similar process raises the pH of some acidic foods. The typical range for bicarbonate in bottled water is 50 to 200 mg/l, but it can reach up to about 1,800 mg/l in waters such as Apollinaris, Gerolsteiner, and Borsec.

Silica  - SiO2

Most adults need between twenty and thirty milligrams of silica daily. [An essential mineral building block, silica is one of the body’s greatest energizing nutrients.] Silica reduces the risk of heart disease and may prevent osteoporosis; it also helps tissue repair by serving as an antioxidant. Hair and nails are strengthened by silica. If bottled waters contain any silica, it’s usually less than 20 mg/l, and the higher levels in waters such as Fiji and Antipodes are well below 100 mg/l.

Trace Elements

The human body needs iron, iodine, copper, fluoride, zinc, and other trace elements as well as minerals. The recommended daily intake is fractions of a milligram for some substances and a few milligrams for others.

 In general a product's shelf life or safe storage time is affected by a number of variables, including intrinsic parameters, such as pH and moisture content, and extrinsic parameters, such as environmental factors. Understanding these variables is key to maintaining a safe food product.

Bottled Water - indefinitely shelf live  under optimal conditions
The FDA has not established a shelf life for bottled water. In the United States bottled water's shelf life is date stamped for two years. This acts as a SKU number and is mainly for stock rotation purposes. It does not imply that the product is compromised after that date. As long as bottled water is packaged in accordance with FDA processing and good manufacturing practices, 21 CFR, Part 129, and is meeting the FDA quality standard provisions as outlined in 21 CFR, Part 165, the product's shelf life should remain intact for an indefinite period of time.

Properly stored bottled water has indefinitely shelf live. However, long-term storage of bottled water may result in aesthetic defects, such as off-odor and taste. IBWA advises consumers to store bottled water in an unopened container at room temperature (or cooler), out of direct sunlight and away from solvents and chemicals such as gasoline, paint thinners and dry cleaning chemicals.

Bottled water is an excellent choice for emergency water storage. FDA Good Manufacturing Practices mandate that bottled water be produced in a sanitary environment and bottled in sanitary, safety-sealed containers.

Tap Water – rotate every six month under optimal conditions
The recommendations are different for water (tap water) that is filled in containers and  stored for an food and water emergency. FEMA recommendations for water that is self bottled are to store the water in thoroughly washed plastic, glass, fiber glass or enamel-lined metal containers. Plastic containers such as soft drink bottles are considered a good choice. The containers need to be sealed tightly, labeled and stored in a cool dark place. The recommendation is to rotate water every six month.

Recently released emergency preparedness guidelines issued by the U.S. Department of Homeland Security recommend that all households maintain an emergency supply of water -- at least one gallon per person per day for three days -- for drinking, cooking and personal hygiene.