Scientifically-speaking, is any water "lost"? Thinking back to those pictures of plains and mountains with a big circular arrow in my seventh grade science textbook: couldn't you say that even the water used by crops, turned into coke, and consumed by humans is eventually returned the ecosystem in some form or another?
It's "lost" if it's taken from where it's needed (the water table near farm land, for instance) to where it isn't (the ocean).
In plenty of areas where water is needed, the time it would take for the big circular arrow "water cycle" to replenish it is so long, it should be considered a finite resource.
