McHenry County, IL Water Table Trend
McHenry County's groundwater trend, from USGS's own readings
Over 56 years of USGS readings, the well tracking McHenry County's aquifer is declining faster than most declining counties: 21.1 ft per decade.
This is one representative well, not a county-wide survey, the same grain limit every page here discloses.
McHenry County's source well, in detail
Depth to water at the last reading was 505 ft below land surface. Readings span 1964-06-08 to 2020-06-17, 14 measurements from USGS well USGS-421432088182801 (44n 8e-33.5a1), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
How McHenry County compares nationally
McHenry County sits at rank 1434th of 1,449 ranked counties, ordered rising-to-declining, so a low number means a rising water table and a high one means fast decline. McHenry County, Illinois is home to about 315,959 people. See the fastest-moving counties guide for how McHenry County stacks up against the most extreme cases nationally.
If you own a well in McHenry County
A dropping water table means a residential pump has to reach deeper and work harder, which shortens its life. In McHenry County, that trend is real, not assumed: 21.1 ft per decade over 56 years.
Depth and quality are separate questions
This page answers a depth question, not a quality one. A well in McHenry County can be stable in depth and still worth testing for quality, or declining and still test clean, the two are measured separately, and only a direct test settles the second one.