BACTERIAL CONTAMINATION

The only required and routine test to be conducted on drinking water from a private well is that for sanitation. The main indicator of the sanitary quality of drinking water is the coliform bacteria count (MCL = average of 1 per 100 ml). A high count of these bacteria is an indication of contamination from a septic system or other fecal pollution source. The presence of coliform bacteria, which can be found in the feces of humans and animals, indicates that there is a high probability of other pathogenic organisms (disease causing germs) present. When water is contaminated with a surface drainage, noncoliform bacteria may also be present in large numbers. This type of contamination may not be harmful since there is only a small probability that drainage water contains pathogenic organisms. However, if the count of noncoliform bacteria is more than 200 per 100 ml, water is also considered to be poor quality.

Superchlorination followed by dechlorination is the most common solution for potential bacteria in the water supply. Mineral and chemical problems found in an individual home water supply are usually a more common concern than bacteria and often require other treatment.