Illinois State Water Survey lab supervisor

Daniel Webb, Illinois State Water Survey lab supervisor, looks at the results of a water test at the University of Illinois lab in Urbana-Champaign. 

Illinois water test map

BLOOMINGTON, Ill. — Just as every acre of land gives a farmer feedback, every sample of water taken from a private well has a different story to tell.

Dan Webb, a chemist at the Illinois State Water Survey, is among those who decipher the story and translate it into a report for the well owner.

Webb’s examination of sample number 239809, taken from a well southeast of Bloomington, Illinois, allowed him to conclude “none of the parameters tested appear unusual or excessive for Illinois ground water.”

This 180-foot-deep well was drilled in 1992 on land converted into a subdivision near the growing city of Bloomington. Today, the well serves seven households.

Arsenic possible in Illinois

In the sample, Webb discovered that arsenic was just above the detectable level, but “well within” the U.S. Environmental Protection Agency’s maximum contaminate level of 10 parts per billion (ppb).

It is naturally occurring across the state, Webb said.

“It’s really hit or miss,” said Walt Kelly, Illinois Water Survey groundwater specialist. Differences in geology mean sometimes there is a high level, and a mile away, none.

Usually reverse osmosis is the treatment for arsenic, he said. Re-testing is recommended after the treatment to make sure it works. Often well owners test both raw water outside and treated water inside to know their treatment is working.

Coliform present

The water sample, taken from the outside pump next to the well, was sent to the McLean County Board of Health to be screened for E. coli and coliform, tests the lab in Champaign does not do.

That’s where the sample had a bigger story to tell.

The Illinois Department of Public Health lab in Springfield found E. coli was less than one per 100 milliliters, which falls within the federal standard.

However, coliform bacteria was present and the lab declared the sample “unsafe for drinking.” The well tested 73.8/100 mL total coliform, significantly above the EPA requirement of less than 1 total coliform per 100 ml.

Coliform aren’t necessarily dangerous, but they usually indicate pollution is entering the water supply and organisms which cause intestinal disease may be present, the report said.

Well owners can contact the health department for details about the disinfection procedures. Short term, organisms are destroyed by bringing the water to a rolling boil for three minutes.

Steve Wilson, a ground water hydrologist with the Illinois Water Survey, said disinfecting can be complicated. He recommends hiring a good contractor to do the work.

All seven families using the well were immediately informed of the recommendation to boil water.

The well group contacted Kickapoo Well Drilling, the company that drilled the well in 1992 and does inspections and often works with the chlorination or recommends other solutions to well owners, said Mark Layten, sales manager.

Sometimes cleaning the water is a process, not one step, he said. The company is determining the best process to chlorinate the water in this case. Well owners pay the cost of the treatment and will receive results of tests showing them when the water is safe to drink again.

Thousands of wells are sampled and every well is different, said John Hendershott, environmental protection programs supervisor at the McLean County Health Department. Nearby homes may be served by different aquifers and wells may be at different depths or have different construction.

Layten with Kickapoo Well Drilling compares getting water from a well for a sample to having gold fish in a bowl. If you dip the net in, you may or may not get a fish if there are only a few, but if the bowl is full of fish, the net will get more. The same goes for testing for contaminants.

At the McLean County Department of Health, the first test for coliform and E. coli costs $21.50. After the well is treated, the department offers a free follow-up test to make sure the water is safe.

Some county health departments offer the initial test free, others charge for both the initial test and any follow-up tests.

People should test water on a regular basis, said Thomas Anderson, environmental health director for the McLean County Department of Health. He suggests putting it on the calendar for every year or 18 months.


Editor’s note: Phyllis Coulter lives in one of the seven households served by the well that was the source of this sample.

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Phyllis Coulter is Northern Illinois field editor, writing for Illinois Farmer Today, Iowa Farmer Today and Missouri Farmer Today.