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 i

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. Ars Technica had a great article about this a few years back, likening "peak water" to "peak oil": http://arstechnica.com/science/2010/05/not-just-oil-us-hit-peak-water-in-1970-and-nobody-noticed/ http://arstechnica.com/science/2010/05/not-just-oil-us-hit-p...