Yellowstone County, MT Water Table Trend
Yellowstone County, MT: what the water table is actually doing
Yellowstone County's representative monitoring well shows depth to water declining at a typical pace for a declining county, a fitted trend of 3.4 ft per decade over 29 years of readings.
One well stands in for Yellowstone 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 22.1 ft below land surface. Readings span 1997-06-16 to 2026-10-06, 148 measurements from USGS well USGS-454202108411801 (01s25e31dcbb01 - Knf 03), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
Where Yellowstone County ranks
Of the 1,449 US counties with a usable trend, Yellowstone County ranks 1259th from fastest-rising to fastest-declining, 1 is the fastest-rising water table measured, 1449 the fastest-declining. About 171,583 people live in Yellowstone County, Montana. See the fastest-moving counties guide for how Yellowstone County stacks up against the most extreme cases nationally.
What a declining table means for a well pump
Because Yellowstone 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 Yellowstone 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.