If I 70kg, per day how many litter water must drink?

It depends. The answer to this question is not easy as water intake depends on your health, how active you are and where you live ( temperature outside) . Just remember that water constitutes 60 to 70 % of your body mass and roughly for a 70 kg man he requires 3 liters ( 13 cups) of water per day whereas women with the same weight require 2.2 liters ( 9 cups).