What Does It Mean if I have Bacteria In My Well Water

A total coliform bacteria test is used to determine the amount of biological contaminants in drinking water. It is easy to perform, inexpensive and should be done at regular intervals for water supplies at risk of contamination. Unlike chemical contaminants that pose a health risk over time, one glass of water containing just a few disease organisms, like E. coli or fecal coliform, can cause illness.

The New Hampshire Department of Environmental Services says that bacterial quality of drinking water is the single most important water quality test. We agree, which is why we offer homeowners water testing services. Not only can we give you tips on how to best collect your water samples, you can pick up and drop off water testing kits at our Skillings & Sons offices.

What Does A Positive E. Coli Or Fecal ColiformTest Mean?

Total coliform is an indicator. Not all coliform bacteria are hazardous to your health, however when bacteria in this group shows up in your water, it indicates the likelihood that disease-causing organisms are also present. On the other hand, if there’s no total coliform in the water, it’s unlikely there are disease-causing organisms there. Labs use total coliform as an indicator test because it is impossible to frequently test for every disease-causing organism.


Total coliform bacteria are found in most soil and can leach into some groundwater and aquifers. In most cases, though, these bacteria are usually filtered out before it gets into a water supply. Having some total coliform bacteria in your water is not itself a health risk, but it does indicate there could be a problem with your well construction, with the water system, or a disturbance of soil or rock surrounding the well.

Fecal coliform is a kind of coliform bacteria that originates from the intestines of animals. As you may suspect, defective sewage systems or animal waste contamination are often the source of this bacteria. Fortunately, they have a relatively short lifespan, But if fecal coliform repeatedly shows up in a water system over time, it indicates a systemic problem, such as a leaking septic tank or defective sewage system nearby.

Escherichia coli, or E. coli, is a kind of fecal coliform that is especially harmful to people’s health. The presence of E. coli means there is a strong likelihood that human or animal waste is getting into the water supply. When this kind of bacteria is found, immediate public notice and a boil order are required.


Using proposed sampling techniques and taking more than one sample are the keys to ensuring good test results. If one out of three samples taken out the same day test positive for bacteria, this indicates contamination of the sample, from either the faucet or the hands of the person taking the sample.

If samples taken at different times show different results, that could mean something different. Because total coliform bacteria don’t live very long the discrepancy could mean the bacteria have died. It can also be affected by heavy rains and home water usage as well.

For help getting the most accurate test results, consult Skillings & Sons. We can help go over your results, explain possible causes and advise you on water treatment options.

Do you suspect your well might be contaminated? Contact us today for a well inspection and water test.