Honolulu County, HI Water Table Trend
Is the water table dropping in Honolulu County, HI?
Honolulu County's representative monitoring well shows depth to water declining, slower than most declining counties, a fitted trend of 0.7 ft per decade over 116 years of readings.
This is one representative well, not a county-wide survey, the same grain limit every page here discloses.
Honolulu County's source well, in detail
Water in this well currently sits 5.7 ft above land surface (flowing/artesian), a flowing or artesian well rather than one pumped from below. Readings span 1910-04-01 to 2026-08-25, 1256 measurements from USGS well USGS-212154158015201 (3-2101-03 Honouliuli (W266), Oahu, Hi), part of the National Water Information System. The qualifying bar and the OLS fit behind this trend are documented in the methodology guide.
How Honolulu County compares nationally
Honolulu County sits at rank 1018th 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. Honolulu County, Hawaii is home to about 998,747 people. See the fastest-moving counties guide for how Honolulu County stacks up against the most extreme cases nationally.
If you own a well in Honolulu County
A dropping water table means a residential pump has to reach deeper and work harder, which shortens its life. In Honolulu County, that trend is real, not assumed: 0.7 ft per decade over 116 years.
Depth and quality are separate questions
This page answers a depth question, not a quality one. A well in Honolulu 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.