It is highly recomended use a carbon pre-filter due to possible heavy metal contamination. You must contact the BLM in Sierra Vista at (520) 439-6400 for current information because sometimes of the year (mostly summer) floods cause run of from the mines and fields near Canena, Mexico to come north arcoss the border causing unsafe water. There are several springs along the river though that provide fresh uncontaminated water if you draw from the source. I'm doing the new trail this weekend and I will give grids to the spings in the write up.
On a side note, if any of you want to do any hiking/need info in the Cochise County area, just send me a PM. I've lived here on and of for nearly 20 years.