This is a straight forward fairly brief yet thorough video explaining why water wars are likely going to be a major problem in the future.
Water shortages are already a big problem for places like Mexico City and Cape Town. Cape Town even began a countdown to their "day zero" when the water would literally run out. Following strict rationing and a laudable effort from the population, they were able to avert the taps literally running dry. Much of it is the result of poor city planning and the draining of rivers to make room for city buildings.
We are becoming better at conserving water but, who knows, maybe "sand baths" will become a thing of the future or maybe we'll go back to our grandparents weekly bath schedule again?!