I called Clorox a few hours ago. The instructions for emergency water purification were as follows. <br> 16 drops per gallon. (thats 1 drop per cup)<br> or 1 teaspoon for five gallons<br> wait 30 minutes before drinking.<br>Buy the regular Clorox, not the scented kind. On the side of the jug is a customer service phone number. They will check to see if you have the proper version of Clorox, by asking you the bar code number, and will give instructions for using it in such a manner.<br> I just tried to filter and purify some water out of a mud puddle in my driveway. One drop per cup is quite strong.<br> I need to work on my makeshift filtration though. I ground some charcoal and sandwiched it between two coffee filters. I placed this inside half a gatorade container. (the one they call the "edge" bottle) It works pretty well, but the coffee filters get clogged up far too fast. At first I thought it was the charcoal clogging the filters, but I had the same result without charcoal. Maybe I will try to find some of that "micro-fine" screen they use in some coffee makers and some high performance automotive oil filters.