What does microbial testing of water primarily check for?

Microbial testing of water is primarily focused on identifying indicators of fecal contamination. This is crucial because the presence of fecal coliform bacteria, for example, can indicate that the water has been contaminated with pathogens that are harmful to human health. These indicators are used as proxies to gauge the potential presence of disease-causing microorganisms, even if those pathogens are not directly tested for. The testing often includes looking for specific bacteria such as E. coli, which is commonly associated with fecal contamination and can cause serious health issues if ingested.

The other options, while important for overall water quality assessment, do not directly pertain to microbial safety. Heavy metals involve a different set of testing protocols focused on chemical contaminants, while pH levels and turbidity relate more to the physical and chemical properties of water rather than its microbiological safety. Hence, the primary focus of microbial testing is indeed on indicators of fecal contamination to ensure water is safe for consumption.