There's no evidence that drinking 2-3 liters of water is necessary or even particularly healthful.
Aaannd... here's a source:
http://www.nytimes.com/2015/08/25/upshot/no-you-do-not-have-to-drink-8-glasses-of-water-a-day.html
My daily liquid (coffee, water etc.) intake is usually ~1litre. I'm still alive.