How much damage will a single bug cause in a room?

Bored at work, I'm staring at a single WCSB that's walking in the center of a large open room. I'm guessing he'll be there for a little while, but I have to know, how much damage will this little guy cause? Will he be able to drink all the water out of the room? Assuming he doesn't meet his demise from a shoe or human activity, would he even be able to cause any damage at all? Would he ever run out of water to drink?