People always drank water, but the ideal water for human consumption must fall within a certain range of parameters. The water's acidity/basicity is only one of these (chemical reactivity).
Chemical reactivity is measured on a logarithmic scale from 0 to 14, where the neutral value is set in the middle pH 7 (pH standing for "potential of Hydrogen" or "power of Hydrogen").
In order to be potable (good for cooking, drinking) the water's pH value should be somewhere between 6.5-8.5.
However, to be considered good for human consumption, natural spring water must also meet other conditions as well.
In general, industrial systems for water distribution supply and ensure these, while bottled water even maintains them for a longer while.
Naturally pH Balanced Clean Water - this is a neutral pH product, with a pH ideally as close as possible to the 7.35 value of the human blood's reactivity.
References: Read more about Water Quality on Wikipedia