Coliform bacteria must be tested for in accordance with the NMED drinking water regulations. What are coliform bacteria?

• A. Pathogens
• B. Indicator Organisms
• C. Nuisance organisms
• D. Non-pathogenic organisms

Answer: (B)

Coliform bacteria serve as indicator organisms in drinking-water testing. Their presence signals potential fecal contamination and suggests that the water treatment barriers may not be fully effective, prompting further testing and corrective action. They’re chosen for this role because they’re common in feces, easy to detect, and their behavior in water reflects the possible presence of pathogens, making them a reliable warning sign. They are not tested as pathogens themselves, and their detection is not about nuisance issues like taste or odor; nor are they simply defined by being non-pathogenic. The main purpose is to gauge overall water quality and treatment integrity, which is why they’re described as indicator organisms.