Will you be able to keep your bottled water cool? If so, then that's probably a good choice. Otherwise, if you're forced to use tap water to reactivate your pouch, use alcohol swabs to clean off your vials/pens/cartridges before you inject. That will kill most bacteria and inactivate most viruses; however, it won't help against your typical waterborne parasites (giardia and crypto). But I wouldn't worry about that... since they are (usually) diarrheal diseases, you're much more likely to get sick from any of them (bacteria, virus, parasite) by ingesting contaminated food/water or not washing your hands than by injecting yourself with a syringe that's gone through the vial stopper that's been prepped with alcohol and which has been exposed to some water that only MAY have been contaminated.
As far as a lack of cool water.... I am not sure since I've never tried, but would lukewarm water work, if you let the pouch soak for a much longer period of time?
