I'm certainly late to clipping this, but just stumbled on a great graphic from Good Magazine about how pharmaceutical drugs end up in our drinking water. It's based on a report last year that showed traces of prescription drugs in the drinking water of major cities. Here's one link to that story: http://www.usatoday.com/news/nation/2008-03-10-drugs-tap-water_N.htm. (Full disclosure: I have written for Good before.)