McLean County, IL Water Table Trend
Is the water table dropping in McLean County, IL?
McLean County's long-term well puts the trend at 13.4 ft per decade, rising, getting shallower over time, based on 16 measurements since 1990.
This is one representative well, not a county-wide survey, the same grain limit every page here discloses.
McLean County's source well, in detail
Depth to water at the last reading was 30.9 ft below land surface. Readings span 1990-01-20 to 2025-06-16, 16 measurements from USGS well USGS-401910089120201 (22n 1w-34.6e), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
How McLean County compares nationally
McLean County sits at rank 19th 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. McLean County, Illinois is home to about 172,069 people. See the fastest-moving counties guide for how McLean County stacks up against the most extreme cases nationally.
Depth and quality are separate questions
This page answers a depth question, not a quality one. A well in McLean 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.