Not sure where you are camping, but it sounds like a boondocking spot.
If it is a regular USFS campground (that charges a fee) they have to test the water on a regular basis to ensure that it is potable.
If not, they likely didn't encourage people to use it for drinking and having water sources for fire is an important consideration for them. That said, it seems like they should have provided some option for people to still get water directly from the ground source, rather than dipping into the tank.
You can certainly purchase filters that allow you to take skunky water with all kinds of junk in it and turn it into safe, drinkable water...but they are not cheap. Berkey is an excellent brand and they make several sizes.
Here's a link for you:
Berkey Filters website