When hydrologists estimate how much fresh water there is?

Question

Is ground water taken into account, or only surface water?

Answer 1

It depends on who is paying them to do the research.  If they were hired by a group trying to be alarmist, they will count only 'pure', fresh water, and cite projections of increased use.

A group looking to deny that the sky is falling, will count all available sources, with no qualifiers, and cite current demand.

So long as you get to define the parameters, you can make data say anything you want it to.