Got drink enough water or not??

A lot of people said, everyday must drink at least 8 cups of water everyday. Big cup? Small cup? Medium Cup? Recently I read an article about this water drinking and the article said we must drink 10 to 15 cups per day. Again, what kind of cup? hehe.. It makes me wonder, how much water I drink everyday?

I believe I drink more water during work than at home but exactly how many litre of water I drink? I decided to find out by bringing water bottles to work. hehe... I brought a 1500ml bottle and a 700ml bottle (which is equivalent to 2.2 litres right?) to work and I did finish all! Besides that, i also drink extra water by using my 500ml thermal mug, at least 3 to 4 mug, so I think add up all I did drink at least 4 litres water per day. wuahahahaha..I wonder 4 litres equals to how many cups of water...

What about you? Do you know how many litres water you drink everyday?