What's In Your Private Water Well?

Typically, groundwater is bacteriologically safe for human consumption because of the natural filtration in ground water. The groundwater aquifer is a reservoir for water and at the same time filter for flowing water. Also, the overlying soil acts as a filter for water percolating into the ground. Groundwater is usually free of disease-causing microorganisms such as E. Coli bacteria and virus. However, contamination may occur following improper installation of well casings or caps, after a break in the casing or as a result of contaminated surface water entering the well. Contamination can also occur if wells are drilled in fractured bedrock without an adequate protective layer and with less than the recommended minimum casing length.

In order to prevent illness, wells should be properly maintained and the water regularly tested for the presence of microbial contaminants. Well water should also be tested occasionally for possible inorganic and organic chemical contaminants.

The bacteriological quality of water produced by a well can change. The probability of contamination is greatest in early spring just after the thaw, after an extended dry spell, following heavy rains or after lengthy periods of non-use.

If you have experienced gastrointestinal illness and suspect that it might be associated with your well water, consult your physician and local health unit. At the same time, ask your self if you are protected. It is possible that such an incidence will make you install a drinking water filter system.

If test results show an unacceptable level of total coliform or E. coli in a well, it is necessary to shock treat the well and, if possible, find and eliminate the source of contamination. Disinfection can be done using unscented household bleach. If the problem persists, then you may want to install a chlorination system on the wellhead.

Nitrate typically originates from farming activities and seepage from septic tanks. High concentrations of nitrate may cause "blue baby syndrome" (methaemoglobinaemia), a condition in which methaemoglobin cannot release oxygen to body tissues, and which mostly affects infants under three months of age. You can install a Nitrate Removal Cartridge in your system to avoid the health risk. Other chemical contaminants of concern include pesticides, heavy metals and volatile organic compounds. If hazardous chemical contaminants are detected, you should consider the installation of a treatment device or a new water supply. As a minimum you should treat the water used for drinking.