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The ABUNDANCE and QUALITY of our regional groundwater resources are in JEOPARDY.


A Regional Challenge

In 2015, the Illinois State Water Survey (“ISWS”) issued its report entitled “Changing Groundwater Levels in the Sandstone Aquifers of Northern Illinois and Southern Wisconsin: Impacts on Available Water Supply” (“2015 Report”), which outlined the long history of its study of available water supplies in northeastern Illinois and shows that, since 2000, the levels of groundwater supply available in the Cambrian-Ordovician Aquifer (deep sandstone) beneath Will, Kane and Kendall Counties and the surrounding areas have continued to decline.  In 2020, the ISWS issued its report entitled “Analysis of Risk to Sandstone Supply in the Southwestern Suburbs: A Report to the Southwest Water Planning Group (SWPG) (Contract Report 2020-04),” dated September, 2020 (“2020 Report”), which quantified the sustainable yield of the deep sandstone aquifer in the southwest suburban region as ranging from 2 to 7 million gallons per day, which is insufficient to support the water needs of communities in the region.

The existing water usage within Will, Kane, Kendall and Grundy Counties and surrounding areas continues to exceed the available yield from the deep sandstone aquifer and, when combined with the anticipated growth in many communities in the region, the continuing availability of a sufficient supply of groundwater from reliable water sources has become an increasing regional concern as local governments seek to protect the public health, safety, and welfare.


In 2020, the ISWS issued a report entitled “Recent Trends in Chloride and Total Dissolved Solids in Silurian Wells in the Southwest Water Planning Group Region: Indicators of Groundwater Contamination within the Silurian Dolomite Aquifer (Contract Report 2020-03),” dated June 2020 (“Shallow Well Report”), which analyzed the levels of chloride and total dissolved solids in Silurian Dolomite Aquifer wells (shallow wells) and found increasing concentrations that can negatively affect water quality and require additional treatment for the removal of these contaminants.

In 2020, the Illinois Environmental Protection Agency conducted water quality sampling of all public water supplies for emerging contaminants such as per- and polyfluoroalkyl substances (“PFAS”) and the results of sampling show that some wells have detectable levels of PFAS in shallow wells at levels already regulated by environmental authorities in other states, and regulation of PFAS will likely be required by either federal or Illinois environmental authorities.

Taken together, the 2015 Report, the 2020 Report, the Shallow Well Report and the IEPA’s detection of PFAS in shallow wells reveal that long-term water supply needs of communities in the region cannot be reliably and

cost-effectively met through the use of groundwater.

The implications of this water-supply challenge are significant, with the potential for profound public health, safety, and economic consequences.
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