How much water do I need to drink when I am 47 kgs?!

There is no clear research on how much a person should drink... However the 'normal' amount for a woman of that weight would be about 4-5litres per 24hrs..

A good indicator is to look at your urine, if its clear then you're hydrated, if it's a darkish yellow - like lucozade then you need to drink more :)

British Army Medic

at least two liters a day. liters and quarts are almost the same. a gallon is 4 quarts, or 3.8 liters. i drink 64 oz. per day. that,s 1.9 liters.