Coliform Bacteria Test FAQ

 
 

Coliform bacteria are present in the environment and feces of all warm-blooded animals and humans.

There are many different kinds of coliform bacteria. Most coliform bacteria are harmless. However, fecal coliform (E. coli) is a type of coliform bacteria and is a health hazard.

Coliform are not naturally found in groundwater. Their presence indicates there is a problem someplace in the water supply. Common causes include:

- Cracks and holes in the well cover

- Cracked well pipe

- Recent work on the water distribution system leading to the home

- Repairs made to the well or home’s plumbing system

- Septic system or animal waste is close to the well

- Contaminated faucet aerator or water filter

The kit is a Presence/Absence test for coliform bacteria. The test will show if coliform bacteria are in the water.
E. coli is one of the coliform bacteria strains. If E. coli is in the water, the test will detect it and show a positive result. If coliform bacteria are found in your water supply, it is an indication that the disease-causing coliform, E. coli, could get in the same way.

The bottle contains a special nutrient blend. When a water sample if added, the nutrients dissolve, turning the water purple/magenta.  If coliform bacteria are in the water, they’ll consume the nutrients. When this happens, the water in the bottle turns bright yellow within 48 hours of starting the test.

Yes. The kit works with well and municipal water supplies.
The water in the bottle will turn bright yellow after 48 hours if kept at 70-77°F (21-25° C).

Consult with your Board of Health or a water treatment professional. Typically, if coliform bacteria are found, a lab should perform a second test to look for E. coli or Fecal Coliform. These bacteria indicate that your water supply has come in contact with human or animal waste, which has a very high risk for transmitting disease.

 
The test works by the activity of bacteria in the water. Cold conditions slow down the bacteria and can lead to inaccurate results. For best results, run the 48-hour incubation period at a temperature of 70-77°F (21-25° C).
 
The test should be viewed after 48 hours, then discarded.  The bottle may turn yellow after 48 hours, but the results are invalid.

The test follows EPA guidelines for sampling water for coliform testing.

No. E. coli don’t survive very well in seawater. A different test method is used to screen beaches and ocean water.

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