if never drink enough, will have bad breath, dry skin
basically drink water is to clear the toxic away, and have better
skin
to see if you have drink enough water, you go see the color of your
urine 
if clear, means you have drink enough
else marz................ 
imo, dont drink over 4 litres
2-3 litres will be good
by drinking water means plain water.. but not cold/ice water..
those normal temp 1
and at night before sleeping dont drink too much
when you wake up, drink 1-2 glasses will be good
