The presence of fecal coliforms, a group of bacteria, and E. coli, a species of fecal coliform, are possible indicators of human and/or animal fecal contamination of water.  Fecal contamination of water can lead to human illness if that water is ingested.  Human and animal feces, leaking septic systems, wastewater treatment plants, and water runoff can all carry fecal coliforms to waterways. 
            The Stream Team measures fecal coliforms and E. coli.  Fecal coliforms are used as an indicator for fecal contamination.  E. coli is a species of fecal coliform that is specific to fecal contamination from mammals.