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Sample Results

Interpreting Your Well Water Test Results

Total Coliform: 0–5
E.coli: 0
Interpretation: Your water is safe for drinking.

Total Coliform: > or = 6
E.coli: 0
Interpretation: Your water is unsafe for drinking unless boiled.

E.coli: 1 or higher
Interpretation: Your water is unsafe for drinking unless boiled.

Total Coliform: est (estimate)
E.coli: est (estimate)
Interpretation: Your water is unsafe for drinking unless boiled.

Total Coliform: o/g (overgrown)
E.coli: o/g (overgrown)
Interpretation: The test was overgrown with non-coliform bacteria making the coliform result unclear, your water is unsafe for drinking unless boiled.

Total Coliform bacteria – refers to bacteria that occur naturally in soil and decaying vegetation. They may also be associated with human or animal fecal contamination. In other words, they are in the dirt, manure and surface water we walk through every day.

Coliform organisms – do not normally grow in well water, because the water is cold (10°C or 50°F) and either alkaline or acidic (pH). The earth has the ability to filter bacteria out as the water moves through the ground. However, once allowed into the well, coliforms will survive for a long time.

E. coli (Escherichia coli) – are bacteria that are found in the intestines of warm-blooded animals like dogs, cats, birds and humans. E. coli is a member of the Coliform family of bacteria. Their presence in the well water may indicate fecal contamination from a human or animal source. There are numerous strains of these bacteria, some of which are very harmful.

E. coli 0157:H7 – is a rare strain of these E. coli that is very toxic. Although it could be found in contaminated water, the presence of E. coli in your water sample does not mean that this toxic strain is present.

Est. means that an estimate number of coliforms and or E. coli bacteria can only be made. There has been an overgrowth of bacteria on the filter media, but the lab is still able to see the growth of some coliforms or E. coli. The numbers are therefore estimated.

Overgrowth (O/G) means that bacteria other than coliforms have overgrown the growth medium in the lab. These other bacteria may feed on iron, sulphur or some other dissolved mineral in the well water or debris that has fallen into the well. These bacteria may hide the presence of Coliform bacteria because they grow faster and bigger covering over the smaller colonies of bacteria on the filter media plate.

Do not drink your water if bacteria are present! See the Drinking Water Precautions section.

If you have completed a mineral or chemical analysis of your well drinking water please call us to help you understand your results.