Somewhat related - measuring consumption by looking for metabolic byproducts in waste water: http://www.guardian.co.uk/world/2005/aug/05/highereducation.resear

Somewhat related - measuring consumption by looking for metabolic byproducts in waste water: http://www.guardian.co.uk/world/2005/aug/05/highereducation.research http://www.guardian.co.uk/world/2005/aug/05/highereducation.... Given some more data points, and the above map - one could get some idea of the amount of money involved.