The health of 44 million Americans who depend upon private wells for drinking water is at risk because of a severe time gap between when private wells are tested for bacteria and when they are likely to become contaminated.

These wells are not federally regulated and are rarely monitored for contamination. State regulators and private well owners are responsible for testing and maintaining clean drinking water for 44 million Americans. Still, there is a gap between the perceived and actual risks of drinking water contamination.

Why Testing is Important

“Water testing is important because it gives people the information they need to manage the health risks they face,” states Baker Center’s Energy and Environment Program Director, Charles Sims. “For example, people prefer to live near clean water and will pay a premium to live in uncontaminated areas.  If people have incorrect information about the bacteria present in their drinking water, they cannot make informed decisions about where to live and work.”

Sims coauthored a paper that suggests testing for groundwater contamination should be optimally timed to ensure the full benefits of testing are realized, and a serious public health issue is avoided. In their study, bacterial contamination was more correlated with temperature than rainfall.  The authors expect contamination to spike in hot summer months instead of immediately after a rainstorm.

How Water Gets Contaminated

Those who live in rural areas, close to industrial and agricultural sources of pollution, are more likely to be at risk of contaminated water due to the lack of access to public water infrastructure. In the study, groundwater became contaminated from manure on nearby livestock operations (hog farms).  Bacteria seeps into the soil and eventually reaches groundwater aquifers. 

The gap comes from the timing of the testing of the groundwater versus when the water is most likely to be contaminated. This can contribute to a false sense of security because these results do not provide the year-round likelihood of bacterial presence in the well water.

When is the Right Time to Test

Using a data analysis of well water near hog lagoons in North Carolina, continuous testing during the colder months (February – April) caused a gap that created false security. The study showed that August’s testing for the bacteria coliform was 34.7 percent, compared to the average monthly minimum that was tested in February at 19.6 percent. The same difference was seen in testing results for E. Coli, results; in July, the results were at 3.73 percent and in February 0.91 percent.

These results show that the risk of bacterial contamination in well water is more accurate when tested during warmer air temperature months. However, it was found that February and March were the second and third most common months for contamination testing, creating a time gap and putting 44 million Americans at risk. The main contaminants this study focused on were total coliform and E. coli.  Most adults will recover from these infections.  But young children can develop severe symptoms including kidney failure. Access to clean drinking water is essential to maintaining global health, promoting sustainable development, and reducing environmental inequities. Click here to read the full paper.