A properly constructed and maintained water well can provide many years of trouble-free service, but over time, wells can deteriorate or become damaged, allowing surface contaminants to enter the water in the well. In addition, groundwater can become contaminated.
Safe drinking water is crucial. Public water systems must monitor water’s safety at least monthly. For private well owners, testing falls on the homeowner. University of Illinois Extension's Doug Gucker recommends annual inspections and testing.
"Spring is the best time to test your well’s water," Gucker says.
Illinois receives its largest amounts of rainfall from April through June. During periods of higher rainfall, surface water may pick up contaminants, such as bacteria, nitrates, or pesticides.
"If the upper part of your well has any cracks or leaks, this contaminated water could find its way into your well," says Gucker. "Additionally, you should test the well’s water after the well has been opened, underwater, or in a fire."
Annual testing for bacteria and nitrates is recommended. Coliform bacteria levels are tested to monitor bacterial safety.
"These bacteria do not usually cause disease or illness, but its presence indicates surface contamination has found its way into your well, alerting you to the possibility other disease-causing organisms may be present."
High nitrate levels in drinking water are a concern for children less than six months old. Nitrogen, in the form of nitrates, is a common contaminant in Illinois groundwater and likely caused by a malfunctioning septic system, animal manure, or runoff from farm fields.
Coliform bacteria and nitrate testing can be done by most local Illinois public health departments. To find your local county health department, visit the Illinois Department of Public Health.
"Consult your local health department to see if you should be testing for other contaminants, such as volatile organic compounds (fuels and oils) or heavy metals, Gucker says. "Certified labs can also test well water and may be your only option for certain chemicals."
Careful water sampling is required to get accurate results from the water testing kit that you received from the local county health department or a certified lab. Read and follow all the instructions included in the testing kit, Gucker advises.
More information on private well water testing can be found on the Illinois Environmental Protection Agency, Well Water Testing website or by contacting your local health department, or the Illinois Department of Public Health at (217) 782-5830.
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