What I meant by "redundant" was the rendering of potable water as "water-of-the-river water." Certainly drinkable water, as opposed to keep-the-dust-down-on-the-road water, is a valid distinction.

Haven't thought of that usage in a long time though (warm thoughts emoticon); I must have stayed too close to big cities for too long, and haven't seen any dirt roads in the summertime lately...