Standard plate test results levels are meaningless re safety for bottled water:

http://www.who.int/water_sanitation_health/dwq/HPCFull.pdf

1.3.1 Bottled water

Bottled (“packaged”) water is considered drinking-water under some regulatory

schemes and as a food in others. Some authorities distinguish between natural

mineral water and other bottled waters. The WHO Guidelines for Drinkingwater

Quality are referred to directly in international norms (Codex

Alimentarius Commission) and are considered applicable to bottled waters.

Bottled waters represent a specific growth situation for microbial flora.

Bottled waters may derive from “pristine” sources (“natural mineral water”) or

from processed waters. They may contain or have added carbon dioxide that

will restrict growth potential, but typically no long-lasting disinfectant residual

is present. The finished product will often be exposed to elevated (ambient)

temperatures over a period of days to weeks before consumption.

Microorganisms naturally occurring in water are a normal part of the

microbiota of bottled waters that meet appropriate safety norms. Levels of HPC

recovered from bottled water post-distribution may therefore sometimes be

significantly higher than those found in municipal water supplies in distribution.

Microbial safety for bottled waters is best pursued by a WSP approach (as

summarized in section 1.2.1). Pseudomonas aeruginosa and HPC values are

used by some as process management indicators in bottled water production and

not as health risk indicators.