Allen County, OH Water Table Trend
Allen County's groundwater trend, from USGS's own readings
Allen County's long-term well puts the trend at 8.5 ft per decade, declining faster than most declining counties, based on 71 measurements since 2010.
This is one representative well, not a county-wide survey, the same grain limit every page here discloses.
Allen County's source well, in detail
Depth to water at the last reading was 34.7 ft below land surface. Readings span 2010-07-23 to 2026-07-16, 71 measurements from USGS well OH015-404325084104000 (Al-5 Oh), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
How Allen County compares nationally
Allen County sits at rank 1371st 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. Allen County, Ohio is home to about 100,866 people. See the fastest-moving counties guide for how Allen County stacks up against the most extreme cases nationally.
If you own a well in Allen County
A dropping water table means a residential pump has to reach deeper and work harder, which shortens its life. In Allen County, that trend is real, not assumed: 8.5 ft per decade over 16 years.
Depth and quality are separate questions
This page answers a depth question, not a quality one. A well in Allen 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.