Final answer:
Non-pathogenic bacteria that are part of the normal flora in water are called nonpathogenic bacteria, which are beneficial and do not cause disease in healthy adults.
Step-by-step explanation:
Non-pathogenic bacteria that are considered to be the normal flora in water are called nonpathogenic bacteria.
These bacteria are well characterized and are not known to consistently cause disease in healthy adult humans.
They can be obligate anaerobic bacteria; abundant in environments such as the human gastrointestinal tract and are usually mutualistic, although some species are opportunistic pathogens.
Bacteria such as Cytophaga provide beneficial roles in aquatic environments with their gliding motility, and Bacteroides are present in the human gut, mostly being mutualistic by helping to prevent pathogenic bacteria from colonizing the large intestine.