What is the primary source of coliforms in a water supply?

The primary source of coliforms in a water supply is fecal material from warm-blooded animals. Coliforms are a group of bacteria, which include E. coli, that are commonly found in the intestines of humans and other warm-blooded animals. When fecal matter enters a water source, it introduces these bacteria into the water, indicating potential contamination and the presence of pathogens that can cause waterborne diseases.

While soil runoff can contain coliforms derived from animal waste, the fecal contamination from warm-blooded animals is specifically noted for its direct link to the presence of coliform bacteria in water systems. Erosion of vegetation and industrial waste typically do not contribute to elevated coliform levels in the same direct way that fecal material does. Therefore, understanding the role of fecal contamination is crucial for monitoring and ensuring water quality in public health.