Hydrohistorian
Groundwater
Three different public records answer the word well in Colorado, and they do not agree on what a well is. A permit is the State Engineer’s permission to construct and use one. A decree is a water right a court has adjudicated, with a place in the priority line. A monitoring well is a hole the state measures the water table in. This section keeps them apart on purpose, and gives each its own index.
The permit file
Every well permit DWR publishes, by division and district — 178,359 of them (56%) for household or domestic use, the kind the exemption in C.R.S. 37-92-602 covers. Only 12% are tied to a decreed structure at all.
Decreed wells
Wells that are the point of diversion for an adjudicated water right — appropriation date, priority, decreed use — browsed by district like ditches and reservoirs. 14,298 of the 51,358 also have a permit DWR ties to their WDID; the rest carry none in the permit file.
The monitoring network
The wells DWR measures water levels in, with the latest cached reading on 2026-07-05. Each well’s page shows its record, its aquifer, and — where the record is long enough — whether the water table there is rising, falling or flat on a Mann–Kendall test.
Learn: Under the Ground
Four lessons on groundwater, each taught on a real well: tributary groundwater is the river, reading a well and an aquifer, pumping now, depletion later, and the three things called “well”, including what is and isn’t known about how exempt wells behave.
What the permit file is made of
DWR’s own permit categories, largest first, and how many of each were ever tied to a decreed structure. The full table is on the permit index.
| Category | Permits | With a WDID |
|---|---|---|
| Residential | 172,122 | 5.2% |
| General Purpose | 44,047 | 40.0% |
| Monitoring/Observation | 35,918 | 0.5% |
| Monitoring Hole (Notice of Intent) | 26,079 | 0.2% |
| Unknown | 19,648 | 2.9% |
| Colorado Water Conservation Board | 8,029 | 0.6% |
None of these records says how much water a well pumps. Household wells are, with narrow statutory exceptions, not metered, and the state keeps no count of wells that have gone dry; the lesson says what is measured and by whom. Locations in the permit file are mostly spotted from section lines, so treat a permit’s point on the map as good to about a mile.