Costilla County, CO Water Table Trend
Costilla County's groundwater trend, from USGS's own readings
Costilla County's representative monitoring well shows depth to water declining faster than most declining counties, a fitted trend of 6.3 ft per decade over 82 years of readings.
This is one representative well, not a county-wide survey, the same grain limit every page here discloses.
Costilla County's source well, in detail
Depth to water at the last reading was 40.6 ft below land surface. Readings span 1944-01-01 to 2026-03-12, 209 measurements from USGS well USGS-372141105281101 (Cc03107207dda), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
How Costilla County compares nationally
Costilla County sits at rank 1341st 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. Costilla County, Colorado is home to about 3,686 people. See the fastest-moving counties guide for how Costilla County stacks up against the most extreme cases nationally.
If you own a well in Costilla County
A dropping water table means a residential pump has to reach deeper and work harder, which shortens its life. In Costilla County, that trend is real, not assumed: 6.3 ft per decade over 82 years.
Depth and quality are separate questions
This page answers a depth question, not a quality one. A well in Costilla 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.