Mercer County, PA Water Table Trend
Mercer County's groundwater trend, from USGS's own readings
Mercer County's representative monitoring well shows depth to water holding roughly steady, a fitted trend of 0.4 ft per decade over 25 years of readings.
This is one representative well, not a county-wide survey, the same grain limit every page here discloses.
Mercer County's source well, in detail
Depth to water at the last reading was 23.9 ft below land surface. Readings span 2001-10-03 to 2026-06-04, 164 measurements from USGS well USGS-412739080104201 (Mr 3306 Mercer County Observation Well), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
How Mercer County compares nationally
Mercer County sits at rank 412th 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. Mercer County, Pennsylvania is home to about 108,140 people. See the fastest-moving counties guide for how Mercer 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 Mercer 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.