What are Coliform Bacteria?
Coliform are family of bacteria that are always present in the digestive tracts of animals, including humans; and are present in their fecal waste. Coliform are also found in plant and soils.
Fecal contamination introduces pathogens (disease causing organisms) to a public or private water source and creates a high risk for contracting diseases which cause very serious illnesses that may result in death. In many situations, concentrations of pathogens from fecal contamination can be low, and the number of different possible pathogens can be high. As a consequence, it is impractical to test for pathogens in every water sample. Instead, the presence of pathogens may determined by testing for an "indicator" organism such as coliform bacteria. Coliform come from the same sources as pathogenic organisms. Coliform bacteria are easy to identify, are usually present in larger concentrations than more dangerous pathogens, and respond to environmental conditions, to wastewater treatment processes, and water treatment processes similarly too many pathogens. As a result, testing for coliform bacteria can be a effective and reliable indication of whether other pathogenic bacteria are, or may be present.
Total Coliform, Fecal Coliform, and E. coli
The most basic test for bacterial contamination of any water source is a test for total coliform bacteria. Total coliform concentration, typically measured as “Parts Per Million” (ppm) provide an indication of the sanitary condition of water being tested.
Total coliform include bacteria that are found human and animal waste, in the soil and organic matter, and in water sources that are influenced by surface water.
Fecal coliform are the group of the total coliform that are present specifically in the digestive tract and feces of warm-blooded animals. Because the origins of fecal coliform are more specific than the origins of the total coliform group of bacteria, fecal coliform are considered a more accurate indication of contamination by animal or human waste.
Escherichia coli (E. coli) is the major species in the fecal coliform group. Of the five general groups of bacteria that make up the family of total coliform, only E. coli is generally not found reproducing in the environment. Consequently, E. coli is the species of coliform bacteria which is the best indicator of fecal pollution and the possibility for the presence of pathogens.
Are Coliform Bacteria Harmful?
The majority of bacteria in the coliform family do not cause disease. However, some rare strains of E. coli, particularly the strain 0157:h7 can cause serious illness. Recent outbreaks of disease caused by E. coli 0157:h7 have generated much public concern about this organism. E. coli 0157:H7 has been found in cattle, chickens, pigs, and sheep. Most of the reported human cases were a result of eating under cooked meat. Cases of E. coli 0157:h7 caused by contaminated drinking water supplies are infrequent but do occur.
Testing is the only reliable way to know if your water is safe. You cannot tell by the look, taste, or smell of the water if disease-causing organisms are present. The Environmental Protection Agency recommends that well owners test their water for coliform bacteria at least once a year. If you have experienced bacteria problems in the past, it is recommended that you test your well more frequently.
When Should I Test?
Coliform contamination is most likely to show up during wet weather so the best times of year to test your well or spring is late spring or early summer. Whether your test results are positive or negative, understand that the sample you collected is just a "snapshot" of your water quality. The more samples you have tested, the more confident you can be about the quality of the water you are drinking. We strongly recommend having a test performed every six months but no less than once per year at a minimum.
What do the results mean?
If coliform bacteria are present in your drinking water, your risk of contracting a water-borne illness is increased. Although total coliform can come from sources other than fecal matter, a positive total coliform sample should be considered an indication of pollution in your well. Positive fecal coliform results, especially positive E. coli results, should be considered indication of fecal pollution in your well.
What can I do if my water test is positive for Coliform Bacteria?
When coliform have been detected, repairs or modifications of the water system may be required. Boiling the water is advised until disinfection and retesting can confirm that contamination has been eliminated. A defective well is often the cause when coliform bacteria are found in well water.
How might Coliform Bacteria get into my water supply?
- Missing, damaged, defective or improperly sealed well cap; poorly sealed wire penetrations, and cracked pipes or fittings.
-Contaminant seepage through the well casing - cracks or holes in the well casing allow water that has not been filtered through the soil to enter the well. This seepage is common in the wells made of concrete, clay tile, or brick
-Contaminant seeping along the outside of the well casing - many older wells were not sealed with grout when they were constructed
-Well flooding - a common problem for wellheads located in subsurface frost pits, in areas that experience frequent flood during wet weather.
Long term options for managing bacterial contamination of a water source
-Installing continuous disinfection and filtration equipment
-Connecting to a public water system, if possible
-Inspecting wells for defects and repairing them, if possible
-Constructing a new well
For further information contact H2o Easy