There are two regulatory groups that oversee water - the EPA and the FDA. The EPA has set an expected standard that heterotrophic testing should show bacterial counts under 500 CFUs (colony forming units of bacteria) per milliliter, yet when it comes to the prepackaged drinking water industry (bottles, cans, pouches, etc.), sadly there seems to be no limit to the amount of bacteria allowed.
We have found up to 10,400 CFU/mL in competitor's waters in the emergency preparedness space. That's equivalent to 10,400,000 Colony Forming Units of Bacteria per Liter of Drinking Water!!
Some experts in the water industry even say that it's sometimes safer to drink city water than some bottled or canned waters. When it comes to Emergency Drinking Water that may sit on a shelf for decades, you should never take chances.
For example, in 2003, the World Health Organization published an in depth study on Heterotrophic Plate Counts in drinking water and concluded the following..