Washington County, MO Water Table Trend
Washington County's groundwater trend, from USGS's own readings
Washington County's long-term well puts the trend at 2.7 ft per decade, declining at a typical pace for a declining county, based on 83 measurements since 1949.
One well stands in for Washington County's whole aquifer here, the honest simplification every page on this site carries.
What the well actually measured
The most recent reading put water 211.9 ft below land surface. Readings span 1949-02-01 to 2026-06-16, 83 measurements from USGS well MO005-375617090465401 (Potosi), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
Where Washington County ranks
Of the 1,449 US counties with a usable trend, Washington County ranks 1233rd from fastest-rising to fastest-declining, 1 is the fastest-rising water table measured, 1449 the fastest-declining. About 23,583 people live in Washington County, Missouri. See the fastest-moving counties guide for how Washington County stacks up against the most extreme cases nationally.
What a declining table means for a well pump
Because Washington County's water table is actually declining, not just a general worry, a well owner here should consider comparing home-warranty plans that cover well-pump failure before one happens.
A dropping table says nothing about water quality
Whether Washington County's water table is rising or falling is independent of what's actually in the water. Depletion can concentrate naturally-occurring minerals, so it's worth checking directly with a water test rather than assuming a depth trend says anything about quality.