I'm enjoying the posts that the water was more of a test for Team Rick than giving them aid or perhaps building trust. I never even considered that. Absolutely, you would want to see their reaction. It could give you some clues about the group. Thanks to everyone for pointing that out.

 

But if you re-watch the episode, when the water gets slapped out of Eugene's hand, it spills on his face and drips down his mouth. If it was poisoned, then he would have been affected by it somehow.

 

You don't know that. Depends on how potent the poison was.

 

Who is to say it was water or poison. It could have been 'pee'

 

I thought it was telling and rather humorous that they were all like...'don't do it, Eugene' but no one except Abe really made even a little move to stop him. I think if it wasn't for Abe, the rest wouldn't have really stopped him until the first bottle was drained.