Also note that flying increases risk of dehydration since the air in airplanes is recirculated and not humidified. This refers to the mineral content of the water. Soft water has fewer minerals than hard water. There are other types of water, the kind you have to buy. This includes distilled water, mineral water, spring water, still water, sparkling water, seltzer water, and plain bottled water.
Distilled water is tap water that had been boiled to steam.
The steam is collected and condensed back into the liquid sans impurities, chemicals, and minerals. This would be the kind of water you would want to use in your humidifier and steam iron if you live in Albuquerque, unless you don't mind having to replace these small appliances every few years due to the mineral buildup. Distilled water is also essential for chemical and pharmaceutical processing. Still water is spring water that has come up to the surface on its own, while sparkling water is pushed to the surface by naturally occurring gasses in the underground spring. Sparkling water will have bubbles and still water won't.