50 miles away from one of the largest freshwater systems on Earth, why is groundwater running out in northeastern Illinois?

Where Chicago-area water comes from

Communities in Cook and DuPage counties get most of their water from Lake Michigan, while Kane, McHenry, Kendall, Will and western Lake counties get theirs from groundwater. Many of the communities that use groundwater draw at least partially from sandstone aquifers.

Note: Data from 2014, some communities may be out of date.

Source: Illinois State Water Survey