Department of Health
- Indicator organisms are a basic monitoring tool used to measure both changes in environmental water quality or conditions, and the potential presence of hard-to-detect pathogenic organisms. An indicator organism provides evidence of the presence or absence of a pathogenic organism that survives under similar physical, chemical, and nutrient conditions.
- It is important to note – an indicator is not necessarily a pathogen. Although some strains of E. coli are pathogenic, the reasons E. coli and Enterococci are used are, because they have been shown to be indicative of recent fecal contamination. In addition, their behavior (viability, longevity, movement) in the environment is assumed to be similar to actual pathogens of concern, and there is a relatively fast method of analysis available.