Which organisms are commonly used as indicators of drinking water contamination?

Coliform groups are widely recognized as indicators of drinking water contamination because they are commonly found in the environment, including in soil, vegetation, and the intestines of warm-blooded animals. Their presence in drinking water suggests potential contamination by fecal matter, indicating that pathogenic microorganisms may also be present. Coliforms are relatively easy to detect and provide a reliable indication of water quality and safety for human consumption.

The use of coliforms for monitoring water quality is based on the understanding that if fecal coliforms are present, there may be a risk of exposure to more harmful bacteria and viruses that can cause illness. Testing for these organisms is therefore a critical part of water quality assessments, as it helps ensure that drinking water remains safe for public consumption.

While other choices like Salmonella, E. coli, and Streptococcus can also indicate contamination or pose health risks, they are not as commonly used as coliform groups for routine assessment in drinking water systems. Coliforms serve as a broader category that encompasses various bacteria, including E. coli, providing a more generalized indication of contamination levels.