I do always, it shows respect.

as for pissing to keep alive, you can, like WW said, if you have a water purifier or something like that, like those little handheld ones, it will remove most bad shit, and it will almost be like water, but after a while, you do need to find real water/food

I always wash my hands with soap, from wrist to fingernail. I don't remember why, but it has something to do with disease and fire. I don't care if I am in a rush, or at someone's home, I am going to wash my hands and you are going to not care.