I keep hearing this argument about water scarcity, but is it true that water is scarce? or clean water is scarce.

Unlike oil, populations are concentrated around water. With improvements in technology to clean and desalinate water, would this market for water still exist?

Oil is limited in quantity, isn't cycled by the environment quickly and must be shipped from the area where it is retrieved to where it is to be used.

To me, this means that clean water technology has huge value, but that water that is already clean is less valuable.