I drink out of the campers fresh water tank. I am careful about where I fill up. I make sure that whatever set up I am getting my water from seems sanitary.
I have had a tank of water or two that didn't smell the greatest. And when I have filled up with city water, I don't like the stench of the chlorine. So now whenever I fill up away from home, I put one of those big blue campco charcoal filters on the hose as I fill. That seems to work pretty good.