The alkalinity or acidity of an aqueous solution are expressed by pH units.
Solutions with a pH less than 7 are acid and solutions with pH higher that 7 are basic or alkaline.
For Acqua Panna natural mineral water: it is considered as a naturally alkaline water. This is given by the fact that the pH of Acqua Panna is 7.9 or higher, directly resulting from its journey through the rocks helping the water to reach such a unique mineral balance.