Three things called “well”

The one-sentence version

A permit is the State Engineer’s permission to construct and use a well. A decree is a water court’s confirmation of a water right — a priority date and a place in line. Every new well in Colorado needs the first. Only wells that must stand in the priority line get the second.

The statute says so directly: a permitting determination “shall neither confer a water right nor preclude determination of a water right by the water court” (C.R.S. § 37-90-137(7)(b)). The permit and the right are different documents from different bodies.

1. How a well gets permitted

Since 1965 every well that diverts groundwater has needed a permit from the State Engineer before a driller can touch the ground. The Division of Water Resources processes well over 10,000 applications a year, and the permit file this site carries is that paperwork — every application, whether it became a well or not. The first thing DWR decides is which of two very different tracks an application is on.

Track one: exempt wells (C.R.S. § 37-92-602)

The 1969 Act that put wells into the priority system carved out small wells “in less densely populated areas” where no other water supply is available. If a proposed well fits one of these boxes, the priority system does not apply to it:

Three practical rules ride along with an exempt permit: one exempt production well per parcel; the house must be on a non-evaporative septic system so the water returns to the ground; and DWR will not issue one where a municipality or district can serve the property. Courts read the exemptions narrowly — if a proposed use does not fit the words of the statute, the well is not exempt (City of Aurora v. State Engineer, 2005).

Track two: non-exempt wells (C.R.S. § 37-90-137)

Irrigation, municipal, industrial, most commercial, and anything over 15 gpm is a non-exempt well. The State Engineer may permit it only on finding that unappropriated water is available and that pumping will not materially injure any senior right. On an over-appropriated stream — which is every stream in the South Platte basin and most of the state — there is no unappropriated water, so the only way to get the permit is to first take a plan for augmentation through water court that replaces the well’s out-of-priority depletions. A permit for a well on over-appropriated ground is issued under that decree, not instead of it.

The same section adds a 600-foot spacing rule from existing wells, and a one-year expiry if the well is not built (one one-year extension) — which is why the file holds tens of thousands of permits with status Permit Expired: applications that never became wells.

Track three: the designated basins

Eight groundwater basins on the eastern plains — Kiowa-Bijou, Lost Creek, Upper Black Squirrel, Upper Big Sandy, Upper Crow Creek, Camp Creek, and the Northern and Southern High Plains — are designated under C.R.S. § 37-90-106. There the water court has no jurisdiction at all; the Colorado Ground Water Commission permits and administers wells under a “modified” prior appropriation. A large-capacity well there gets a conditional permit, then a Final Permit once beneficial use is proved (§ 37-90-108); Denver Basin bedrock wells get a Basin Determination of the water under the land (§ 37-90-107(7)). Small-capacity wells there (≤ 50 gpm, § 37-90-105) play the household role the exempt well plays elsewhere. Those category names are in the table below, and they behave very differently from a Residential permit.

2. How a permitted well may be used

The permit’s conditions of approval are the whole of what the well may lawfully do. A household-use-only well that fills a stock tank or waters a lawn is out of compliance even though nobody is short of water; the 15 gpm cap and the one-acre limit are permit terms, not suggestions. Two things on a permit page tell you the shape of the allowed use:

• Uses (DWR’s associated uses): household, domestic, stock, irrigation, commercial, municipal, monitoring… This is the legal purpose, not what the owner happens to do.
• Category: DWR’s own bucket for the permit type — Residential, General Purpose, Monitoring/Observation, Final Permit, Basin Determination… The category tells you which track the permit was issued on.

A wrinkle from DWR’s own guidance (Guideline 2023-1): a permit labelled simply Domestic and issued before July 1, 2001 implicitly allowed watering domestic animals; one issued after that date must say so. The label on an old permit is not quite the label on a new one.

3. How the two kinds of well are administered

This is the part that is confusing even to people who work in water, so it is worth being exact about the words. An exempt well is exempt from administration in the water-right priority system — DWR’s phrase. It is not exempt from needing a permit, from its pumping limits, or from the law. What it is exempt from is the call: when the river goes under administration and juniors are curtailed, a division engineer does not shut off household wells. The statute presumes they cause no material injury, and the legislature said it “does not intend” them to injure anyone — while also saying they may be required to augment “wherever possible.”

A non-exempt well is the opposite case. It stands in the same priority line as every ditch and reservoir on the river (lesson A1). It has an appropriation date and, through the augmentation plan or its own adjudication, a decree. When the call comes its depletions must be covered by replacement water or it is curtailed like any other junior — and because a well’s depletion reaches the stream late (lesson D3), that replacement may be owed for years after the pump stops.

Can an exempt well be decreed? Yes. Section 602(4) lets an owner adjudicate an exempt well, and if they do, the court awards the well its original priority date regardless of when they applied. Almost nobody bothers: the point of the exemption is that the well does not need a place in line. But it is why a small number of household permits carry a WDID and appear on the decreed side of this site.

4. Where the two datasets meet

The seam between the permit file and the decreed record is a single field: the WDID. When a permitted well is also a decreed structure, DWR ties the permit to the structure’s WDID, and this site links the two pages both ways. When it is not — which is most of the time — the permit stands alone, keyed only by its receipt number.

Here is the whole file by DWR category, with how many of each ever acquired a WDID. Read the last column as “how much of this category lives on the decreed side too”:

* DWR’s status vocabulary differs by track. A designated-basin Final Permit or Basin Determination carries its own status rather than “Well Constructed,” so this column reads 0% for them even though a final permit is, by definition, a built well in beneficial use. On the exempt and non-exempt tracks the gap between this column and 100% is mostly applications that expired, were denied, or were later abandoned.

The pattern is the law made visible. Residential permits — the exempt household track — almost never carry a WDID, because they never needed a decree. Final Permit and Basin Determination almost always do, because in a designated basin the permit is the administered right and DWR gives it a structure record. General Purpose sits in between: it is the non-exempt track, where the ones that went through an augmentation plan have a WDID and the expired or denied applications do not.

• 320,406 permits in the file; 37,239 (11.6%) carry a WDID, pointing at 30,053 distinct structures.
• Of those structures, 30,045 are in this site’s structure index and 14,350 hold a decreed right. The rest are DWR structure records the site has not loaded, or structures with no decree at all (a designated-basin permit, a plugged well).
• From the other side: the site knows 80,111 structures of well type statewide, 51,358 with a decree — and 14,298 of those have a permit on file here. The rest were decreed but permitted in a division not yet loaded, or predate the permit system (wells in production before 1957 were registered, not permitted).

These numbers come from the same index the map draws, rebuilt nightly; they will move as more divisions are loaded.

The Driller’s Atlas · Plate 2 A cross-section nobody surveyed

Every permitted well within a few miles of the line, drawn from the ground to its drilled depth as the driller filed it. The bright part of each stroke is the perforated casing — where the well actually takes water — coloured by the aquifer named on the permit. Nobody arranged these; the aquifers arrange themselves.

Line the Denver Basin, Roxborough east to Kiowa (39.35° N) the Denver Basin, Parker south to Colorado Springs (104.75° W) the South Platte valley, Greeley east to Fort Morgan the Ogallala, Burlington north to Wray Corridor ±2 miles ±4 miles ±8 miles Load the cross-section

Hover or arrow through the strokes to read a well.

The same corridor as a table

Miles from A	Wells drawn	Median depth (ft)	With a screen	Most-named aquifer	No depth filed

Bins run from end A to end B of the line. “Most-named aquifer” is the family most often named on permits in the bin, with its count; permits naming no aquifer are the majority of the file and are not a family.

The Denver Basin’s bedrock aquifers are, by the State Engineer’s own rules, a stack: Dawson on top, then Denver, Arapahoe and Laramie–Fox Hills (2 CCR 402-6). The plate does not draw that stack; it draws what the drillers filed, one lot at a time, and lets you check the legend against the strokes yourself. It shows how deep wells were drilled and where they were screened. It does not show water levels, yields or use, which the file does not measure (section 6). Every district page carries the same plate with a line you can draw.

5. Three records, one word

Merging these into one list would misstate all three. A monitoring well’s falling water table is a fact about the aquifer, not a claim about anyone’s right to it — exactly the mistake lesson D2 warns against. A decreed well right stands in the priority line; a household permit was built to sit outside that line on purpose. So a search for “my well” by receipt or permit number, not by WDID, is usually the right instinct — and the /wells hub says as much when a decreed search comes up empty.

6. What is and isn’t known about how these wells behave

Readers ask three fair questions about exempt wells: how much water do they use, do they go dry, and are they less reliable in some years? The honest answer to each starts with what the record does not contain. Every statement below is quoted or paraphrased from a primary source, and this site adds no numbers of its own.

How much water do they use? Nobody measures it.

An exempt well is not metered and its pumping is not reported to anyone. The exemption statute contains no metering or reporting requirement for household wells; its only metering clause reserves the State Engineer’s power to require “metering of withdrawals, periodic reporting of such withdrawals” within a cluster development (C.R.S. § 37-92-602(3)(b)(II)(D)) — that absence elsewhere is our reading of the text, not a DWR statement. So every per-well figure you will meet is a planning assumption, not a measurement:

• DWR’s current well-permitting guideline assigns 0.3 acre-feet per year for “ordinary household purposes inside 1 single family dwelling,” 0.05 for “the watering of 4 of the user’s own domestic animals,” and 0.05 for “the irrigation of 1,000 square-feet of home lawn and garden” (DWR Well Permitting Guideline 2023-1, § 11.1).
• The USGS Denver Basin model adopted DWR’s 1998 factors: “0.6 acre-ft/yr for domestic and livestock wells, 0.3 acre-ft/yr for household-use only wells,” with domestic-and-livestock wells assumed at 50 percent consumptive use and household-only at 10 percent (USGS Professional Paper 1770, ch. B, p. 101).
• On those assumptions, USGS estimated that domestic wells were about 12 percent of all Denver Basin pumping in 2003 and 28 percent of bedrock-aquifer pumping (PP 1770, ch. B, p. 177). That is a count of wells multiplied by an assumed rate, and USGS presents it as such.

We could not find a statewide or basin-wide total for exempt-well withdrawals in the State Water Plan, SWSI, or any DWR study; if one exists, it is not published where we looked.

Do they go dry? The state does not keep track.

Asked exactly this in July 2025, Colorado’s Deputy State Engineer answered on the record: “We don’t specifically keep track of dry when wells go dry. Typically we would get a replacement permit application if someone’s well goes dry. So we can kind of see trends that way … but someone might be replacing a well for a different reason other than the well going dry. So, it’s not definitive.” DWR has only recently begun recording dry holes — wells drilled that never hit water — and “we do not have a good existing database of those wells.” And: “We issue a well permit, but we don’t guarantee that you’re going to find water” (Sarah Brucker, Colorado Division of Water Resources, interviewed by CPR News, 9 July 2025).

That is why this site does not count dry wells either. The permit file carries a “replaced” status with no date or reason, which is the same non-definitive proxy DWR describes; we leave those rows visible on each permit page and do not total them into a claim. A replacement well, in statute, is simply a new well that “shall be limited to the yield of the original well and shall take the date of priority of the original well” (C.R.S. § 37-90-103(13)); an exempt well may be relocated without a new decree if it is “within two hundred feet of the existing well” in the same aquifer with unchanged use (§ 37-92-602(3)(c)).

Are they less reliable in some years? Two things are actually measured.

• Foothills fractured rock. The Colorado Geological Survey, writing during the 2002 drought: “Wells tapping this type of aquifer are very vulnerable to an extended drought period of a dry winter followed by a dry spring, as happened in 2002. In addition, there is little chance of recovery until the following spring, given typical precipitation cycles” (CGS RockTalk 5(4), Oct. 2002, p. 10). The same primer notes that alluvial aquifers, by contrast, held “relatively stable water levels during dry periods.” In Turkey Creek, Jefferson County, where about 4,900 households were on domestic wells, USGS found a median reported well yield of 4 gallons per minute (USGS WRIR 03-4034).
• Denver Basin bedrock. USGS runs water-level networks of 36 wells in Douglas County (a domestic-well network, established 2011) and 36 wells in Elbert County (2015). Douglas County 2011–19: wells with significant trends had medians of −0.23, −0.31, −0.92 and −2.26 feet per year in the upper Dawson, lower Dawson, Denver and Arapahoe aquifers (USGS SIR 2020-5076). Elbert County 2015–23: −0.23, −0.66, −0.64, −0.39 and −0.63 feet per year in the upper Dawson, lower Dawson, Denver, Arapahoe and Laramie-Fox Hills, with departures from 2015 levels “greatest during the dry period between 2020 and 2023” (USGS SIR 2026-5115). Basin-wide, USGS simulated about 690,000 acre-feet removed from bedrock-aquifer storage by 2003 (PP 1770, ch. B). None of those numbers is a dry-well count; they are water tables, measured.

The only live instrument this site has on the question is the same kind of record: the groundwater-level monitoring network, most of whose wells are not household wells at all. A falling water table in a nearby monitoring well is evidence about the aquifer; it is not a statement about any particular exempt well.

What this does not let you conclude

Section 6 quotes sources on what is not measured; treat the planning figures there as exactly that, and do not multiply them by this site’s permit counts to manufacture a withdrawal total — we have declined to, on purpose. A permit in the file is not a well in the ground: expired, denied, withdrawn and abandoned permits are all kept, and a monitoring-hole notice was never a water supply. A structure can appear in more than one of these datasets at once — a decreed well right can also have its own groundwater-level record, and the dossier links to it when it does. None of the three pages determines whether a specific well is tributary, whether it is in compliance with its permit, what it may lawfully pump, or how it must be augmented; those are engineering and legal determinations. Statute cited: C.R.S. §§ 37-90-105, -106, -107, -108, -137 and 37-92-602; DWR Guide to Colorado Well Permits, Water Rights, and Water Administration (2012) and Well Permitting Guideline 2023-1; USGS Professional Paper 1770 ch. B (2011), WRIR 03-4034 (2003), SIR 2014-5172, 2020-5076 and 2026-5115; CGS RockTalk 5(4) (2002); CPR News, 9 July 2025 — read the sources, not our summary, before relying on any of it. Advisory reading aid on public data — never an administrative or legal conclusion, and never a substitute for DWR administration or an engineer’s analysis. Our methodology has not yet had outside expert review: how this is built.