We are planning a extended trip to Big Ben National Park in March 2014. I received a note from a friend who just came from there. They said "The resorts at Big Bend National Park have their own water ...
when we camped at the Rio Grande Village a few years back (the only CG with RV hookups in the park) we hooked up to the water and did not notice any problems, taste or otherwise. if that's where you are planning to stay be advised that it is a blacktopped parking lot. march should be fine but it can get hot...very very hot. we were there in late September and left after 3-days as the AC was barely keeping the coach interior below 90.