Linn County, IA Water Table Trend
Linn County's groundwater trend, from USGS's own readings
Linn County's representative monitoring well shows depth to water rising, getting shallower over time, a fitted trend of 3.6 ft per decade over 32 years of readings.
This is one representative well, not a county-wide survey, the same grain limit every page here discloses.
Linn County's source well, in detail
Depth to water at the last reading was 1.9 ft below land surface. Readings span 1994-12-01 to 2026-09-29, 81 measurements from USGS well USGS-415949091405402 (083n07w17dac 1993usgs Crm-12), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
How Linn County compares nationally
Linn County sits at rank 79th 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. Linn County, Iowa is home to about 231,762 people. See the fastest-moving counties guide for how Linn 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 Linn 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.