What is Coliform?

Coliform is a bacteria that is present in nature and occurs in all human and animal waste.

The bacteria itself is not considered harmful, however the coliform bacteria in drinking water can indicate a possible presence of harmful, disease-causing organisms. These organisms are called pathogens and can be viruses, protozoa or bacteria. Common examples of these pathogens are dysentery and hepatitis.

Coliform is considered a water quality indicator because it can be associated with the sources of pathogens. To test for all the pathogens would be extremely expensive, so Coliform is used as a simple broad test that is economical. Specific testing for independent pathogens is generally done only when an outbreak of a waterborne disease occurs.


Types of Coliform

Total Coliform Bacteria

Commonly found in the soil or vegetation and typically harmless. If only total coliform is found in the drinking water, the source is generally environmental and fecal contamination is not very likely.

E. coli Fecal Coliform Bacteria

This bacteria is a subset of total coliform. These bacteria occur in large quantities in the feces of humans and animals. Generally the presence of Fecal Coliform signifies recent contamination, indicating that there is a greater risk that pathogens are present as well. The risk is much higher if fecal coliform is discovered than total coliform.

E. coli 0157:H7

This is one of hundreds of strains of Fecal Coliform Bacteria. Most strains are harmless and occur normally in the intestines of healthy humans and animals, however, this strain produces a powerful toxin and can cause severe illness. Infection often causes severe bloody diarrhea and abdominal cramps; sometimes the infection causes non-bloody diarrhea. Frequently, no fever is present. It should be noted that these symptoms are common to a variety of diseases, and may be caused by sources other than contaminated drinking water.


How Do I Remove Coliform Bacteria From My Drinking Water?

The water can be treated using chlorine, ultraviolet treatment system or ozone, all of which act to kill or inactivate E. coli. Systems using surface water sources are required to disinfect to ensure that all bacterial contamination is inactivated, such as E. coli. Chlorination does not guarantee removal of bacteria from drinking water.

If you think you have coliform in your drinking water, contact one of our specialists to discuss your options.