What are the basic features about water?
Natural Water versus Processed Water
Great waters are bottled as they come from the ground (occasionally an overriding national regulation may impose a safety process on the part of every bottler that is unnecessary, but is complied with as a matter of law). Great waters need no cleansing, disinfecting, filtration, carbonation, chlorine, ultraviolet or ozone debacterialization, nor do they need any "polishing," a practice of introducing trace elements in an attempt to make a cheap processed water "taste" somehow better or different. This process invariably backfires, putting in an unnatural flavor or aftertaste.
Natures - There are three natures for water:
TDS stands for Total Dissolved Solids. It is the overall measurement of the amount of minerals suspended in the water. To show the extremes, distilled water (which does not occur naturally anywhere in the world, and is ideal for irons and radiators, not humans) has a TDS of 0. The highest TDS natural waters have a TDS approaching 3,000. The actual measurement is "milligrams per liter"; also known as "parts per million."
An example of a very good very high-TDS water is Apollinaris, at 2,650.
pH technically stands for "percent hydrogen." In simple language, the pH is the acidity or alkalinity of taste. Acidity is the sour taste exemplified by lemons, and vinegar. Alkalinity is the tart/bitter taste associated with bicarbonate of soda, and (I remember saying a bad word as a little boy) soap. The way pH works is on a balance beam scale where the middle is 7.0. Any substance that is perfectly neutral in pH, possessing no acidity or alkalinity, has 7.0 pH. Distilled water has a 7.0 - and great natural waters can range from the mid-5s all the up to the mid 9s. Most are pH's of great waters are clustered between the low 6s and the high 7s.
Of course, there is some relationship between the TDS and the pH, but not as much as you might imagine. For example, there are very high-TDS waters with high, neutral, and most often low pH values. The same is true of the other TDS ranges. This variegation creates a spectacular opportunity to identify the waters that best suit your body chemistry and your taste.
Packaging is both an issue of practicality, and subjectivity. Fine dining calls for glass, and portability normally connotes plastic. Within the glass and plastic families, there are quality groups as follows:
You can devote an entire academic career to the study of water. Over fifty nations have university level graduate programs on industrial applications and systems for human drinking water. Some universities also offer courses of study on "food anthropology," a topic that addresses the placement and sociology of food and water consumption over recorded history.