I've been doing a little experiment.  The coffee maker looking appliance you see here is a water distiller.  It distils about a gallon of water in 6 hours.  The erlenmeyer flask with the cola-looking liquid in it is what is left in the bottom of the distiller after it's done.  The quantity of brown liquid you see here is from 15 gallons of tap water.  Each gallon yields about 3 to 5 mL of this stuff.  When I first arrived here I was drinking tap water by the gallons, then veteran teachers told me about the distillers so I decided to try one.  Boy, am I glad I did!  My house mate Tim got us a Brita filter so between these two items we have copious amounts of good tasting H2O.