Spring is an important time of year for people who rely on well water or a private well for their drinking water supply.
The groundwater which supplies your well starts as precipitation in the form of melting snow and spring rains. In the spring, precipitation recharges the groundwater supply. Because this recharge of groundwater can occur rapidly, wells can quickly become contaminated by bacteria if it is present. This is especially true for wells located in karst regions–areas where soil layers are thin or absent and bedrock is highly fractured. Some well owners may actually notice their well water change its appearance or odor after a large rain or snowmelt.
Coliform bacteria tests are an easy way to determine whether your water supply is free from harmful bacteria. Coliform bacteria are common in soils and are not generally considered harmful to health, however; they are also found in human and animal waste. For this reason a coliform bacteria test is used as an indication of the sanitary condition of a water supply.
A sanitary water supply or properly constructed well should not contain any coliform bacteria; the bacteria’s presence in well water means that a pathway exists for other potentially dangerous pathogens such as E. coli, a type of fecal coliform, to enter the water supply. If pathogens are present, a variety of illnesses could occur from drinking the water. You should test your well water annually for coliform bacteria or any time you notice a sudden change in color, odor or taste; think of it like going to the doctor for a check-up.
In addition to coliform bacteria, there are a number of other contaminants for which well owners should consider testing. Some of these include human-related contaminants such as nitrate and pesticides or naturally occurring contaminants such as arsenic. The Oconto County Extension office can help you with sampling your water. Contact us at 920-834-6845.
Visit the Department of Natural Resources website for more information and answers to some of the most common questions concerning well water and well testing in Wisconsin.