Lemme see...
Crunching numbers, i drink about 600ml x 5-6 times, so lets say = 3-3.5Litres?
Ya know, thats just during the day, if i wake up at night, i down atleast a glass, maybe two... which is about 1/2 a litre more.
:)
Also, these numbers are not counting water drunk while at the gym...