Montana water data · County
Fergus County: well depth, groundwater and water rights
What the public record says about water in Fergus County: how deep wells go, where the water table sits, what wells produce, which water rights are on file, and which documented environmental sites are nearby. Area statistics orient you; a property report analyzes the records around one specific parcel.
Updated September 2026 · Based on 17,572 public records from MBMG GWIC, Montana DNRC, Montana DEQ, EPA SEMS, EPA UST Finder
Wells on record
3,856
3,637 with recorded depth
Median well depth
126 ft
half of wells 50–300 ft
Median static water level
32 ft
2,941 measurements
Median tested yield
15 gpm
3,019 pump tests
Well depth
How deep are wells in Fergus County?
Of 3,637 wells with a recorded total depth, the median is 126 feet. Half were drilled between 50 and 300 feet; one in ten went deeper than 600 feet and one in ten found water shallower than 21 feet. Depth is set by local geology and position on the landscape, both of which change over short distances, so the spread matters as much as the median.
Static water level
32 ft
median depth to water at rest · half between 14 and 75 ft
The static level is how far below ground the water stands before pumping, measured by the driller at completion. It affects pump setting and operating cost, and it moves with season and with neighbouring use.
Well yield
15 gpm
median tested yield · half between 8 and 25 gpm
13% of tested wells produced under 5 gallons per minute and 41% produced 20 or more. These are short completion tests, not sustained-capacity tests; a household typically needs 3 to 5 gpm with storage.
Drilling activity
Recent well drilling in Fergus County
552 wells have been completed here since 2016, 18 of them in the last twelve months. The newest log on file was completed June 27, 2026. Records run back to 1865.
What the wells are for
- Domestic2,070
- Stockwater1,673
- Monitoring462
- Irrigation270
- Public Water Supply44
How they were drilled
- Rotary1,685
- Forward Rotary359
- Unknown214
- Solid Stem Auger159
Drillers filing well logs in Fergus County
- Central Drilling Inc240 since 2016 · 2026
- Montana Salinity Control Association159 since 2016 · 2021
- Singley Drilling59 since 2016 · 2026
- Hole World Consulting Llc30 since 2016 · 2025
- Haz Tech Drilling Inc17 since 2016 · 2020
- Aquasource Drilling Llc8 since 2016 · 2024
- Olympus Technical Services7 since 2016 · 2022
- Vidic Drilling Inc6 since 2016 · 2024
Ranked by well logs filed with GWIC, public record only. Not an endorsement, a referral or a paid listing; we have no business relationship with these companies. Verify licensing with the Montana Board of Water Well Contractors before hiring.
Water rights
Water rights on file in Fergus County
Montana DNRC lists 13,444 water rights in the county: 5,243 groundwater and 8,201 surface water, 12,390 of them active. The median priority date is 1950, and the oldest claim dates to 1870.
Types of right
- Statement Of Claim9,637
- Ground Water Certificate2,625
- Stockwater Permit510
- Provisional Permit411
- Exempt Notice209
Purposes
- Stock8,754
- Irrigation1,334
- Domestic1,079
- Wildlife333
- Domestic; Stock330
DNRC basins
- 41S5,990
- 40B3,746
- 40EJ1,423
- 41T1,195
- 40C710
Area totals describe the neighbourhood, not any one parcel. Montana publishes no authoritative link between a parcel and a water right; whether a right attaches to a specific property is a property-level question that our reports answer with the DNRC abstract linked.
Aquifers and geology
What wells in Fergus County draw from
Drillers record the aquifer a well is completed in. The units below account for the wells here that carry an aquifer assignment; the median depth beside each is for wells completed in that unit.
- Kootenai Formation128 wells · 26% · median 355 ft
- Eagle Sandstone101 wells · 21% · median 1,720 ft
- Judith River Formation (of Montana Group)89 wells · 18% · median 397 ft
- Third Cat Creek Sandstone (basal Kootenai Fm)29 wells · 6% · median 900 ft
- Colorado Shale Or Fm. (of Colorado Group)28 wells · 6% · median 83 ft
Aquifer assignments are the driller's, recorded at completion, and many older logs carry none. Absence of an assignment is not evidence about the geology.
Environmental groundwater screening
Documented environmental sites in Fergus County
Petroleum releases
104
16 open · 88 resolved
Superfund program sites
2
none on the National Priorities List
Registered tank facilities
166
underground storage tanks, current and historical
A documented release or site in the area is not evidence that any particular well is affected. Whether a release reaches a well depends on groundwater flow direction, geology, well depth and construction, the extent of the plume and the cleanup performed. The most recent release reported here dates to 2021. A property report screens the sites within a quarter, half and one mile of a specific parcel and links the agency records.