ok this might be duh question for some of ya'll out there. How do you know or determine how much water you have used out a hydrant on a structure fire? In Tennessee we are suppose to be keeping up with the amounts of water used. I have tried a search on the net and no results. The only thing I have been able to come up with is just guessing. I know there is no way to get an accurate amount but how can I get a ball park figure.