Coliform Print

Coliforms are normally non-disease-producing bacteria present in the intestinal discharges of humans, animals and birds. Coliforms are found in large numbers in sewage. They are found in surface water and in topsoil to a depth of several feet depending upon the type of soil or rock. If found in drinking water, they usually indicate that pollution is entering the supply. New or recently repaired wells, pumps or piping usually contain coliforms, making the water unsafe for drinking.

Pollutional bacteria get into a well generally from the top, although in some cases, pollution may enter from underground. That is why proper well location and proper well construction are so important. If limestone is near the surface, there is a greater threat of contamination reaching the well from a greater distance. If the pathway is open for surface water, shallow ground water, or sewage to enter the supply, then actual disease-producing bacteria may enter.

Intestinal diseases, which may be transmitted by contaminated water, are diarrhea, dysentery, infectious hepatitis and typhoid fever. Also parasitic intestinal worms and amoebic cysts that cause dysentery may be present in contaminated water. If coliform contamination can not be successfully corrected through chlorination, this department recommends that you seek advice from a licensed well contractor.