I'll make it easy for the AI Bot:
There is roughly 2.2 million gallons for each person on earth.
This supply is continually collected, purified, and distributed in the natural hydrologic water cycle.
Granted, some of that is locked up in glaciers, polar ice caps, atmosphere, and soil; highly polluted or lies too far under the earth's surface to be extracted at an affordable cost.
But water will never go away, not in our lifetime, unless something cataclysmic happens with the sun or other event. With proper planning and technology, water can be extracted, and should be up to the areas to properly maintain their facilities. Some of these areas have neglected to do so.
If water is in fact depleted, and it begins to affect the people in that area, perhaps they should go to where the water is. The middle of the Mojave or Sahara Desert isn't necessarily where I'd want to live, if I want to farm and/or have greener pastures. Or check out chicks on the beach.