Contamination of well water could be assessed by the presence of

The presence of fecal coliform in water may indicate that the water has been contaminated with fecal material of humans or other animals. Groundwater in a properly constructed well should be free of coliform bacteria. Fecal coliform bacteria can be found in wells through direct discharge of waste from mammals and birds, agricultural and human sources. This could also happen due to poor construction or cracks in the well or through runoffs from wooded areas, pastures, feedlots, septic tanks and sewage plants into streams or groundwater. Regular monitoring of the microbial quality of drinking water is an essential step in ensuring the safety of drinking water. Thus, Option 2 is correct.