Water , previously assumed to be freely available, is neither free nor available.

Have a look at the figures.
2.5 % of the world's total water is fresh water , rest is salty water .

Of this, less than 1% is accessible surface water (68% is locked in icecaps and glaciers and more than 31% is inaccessible ground and surface water .) Out of this, 2% is available for domestic consumption.
But even this quantity would be sufficient for fulfilling the requirement of everyone.

So what is the problem?
The problem , apart from uneven distribution of the world's water, is twofold.
First , the required amount of water is not available to the people due to lack of infrastructure.
Second , and this is the greater problem, contamination of water, and thus non availability of potable water.

In fact dirty water is the greater and much more intractable problem than water scarcity.

The future, regarding potable water, is bleak .
And the future is now.