TOO EARLY TO DEFINE good bacteria for possible probiotic water. “More research is needed to clarify the role of probiotics for preventing antibiotic-associated diarrhea, Clostridium difficile infection, travelers’ diarrhea, irritable bowel syndrome, ulcerative colitis, Crohn’s disease, and vulvovaginal candidiasis.” However, identifying the pathogens to exclude in drinking water is easy.
http://www.ajhp.org/content/67/6/449.short