It appears there are two issues being commingled here.
1. Do you drink from your tank?
If you put good water in and properly care for your system then you will get good water out.
2. Poor campground water available.
If the local water is poor quality I wouldn't drink it either but it really has nothing to do with drinking from the tank. (see #1 above)
Since most municipal systems use water tanks to maintain steady pressure and most wells also use a tank for the same reason - guess what? We all are drinking from a tank somewhere unless you are drinking straight from surface water.
For that matter, what is the difference between a bottle and a tank? Aren't they both a vessel that stores and carries water?
Good water in=good water out.
