PH 7 is neutral, below 7 is acidic, above 7 below 8.5 is weakly alkaline, and above 9.5 is strongly alkaline.
The recommended value of drinking weakly alkaline water is around 8-8.5, and drinking alkaline water above 8.5 should be under the guidance of a doctor.
Note that all kinds of alkaline water cups or micro-electrolytic water cups are purely bluffing.