Thanks for the info - most of my rafting has been down south there. I found a bunch of references (BLM, OARS, etc) that using bronners and campsuds is acceptable - but only off the river as you pointed out (above the high water line). This includes not using it in any hot springs (duh) or other spring or side water source. FYI - these guides were specifically for the MF, LS & MS.
Again - thanks for the guidance. Since I'm typically the chief bottle washer - I'll share this with the rest of the group.
"It's supposed to be hard. If it wasn't hard, everyone would do it. The hard... is what makes it great."