2 hours 37 minutes. Right before S3 ended when the midsummer event launched the servers were crap. My rogue and the other team's warrior dc'd at the exact same time. resto sham v. disc priest fun ensued! 2 hrs later i ran out of water. 37 minutes later i finally died (was kinda getting bored/sleepy).
EDIT: Since it was due to DC, neither had to worry about a rez. I even got up to go take a quick bio mid-game and lived thru it!