Montana water data · County
Fallon County: well depth, groundwater and water rights
What the public record says about water in Fallon 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 5,894 public records from MBMG GWIC, Montana DNRC, Montana DEQ, EPA UST Finder
Wells on record
1,882
1,760 with recorded depth
Median well depth
180 ft
half of wells 82–400 ft
Median static water level
70 ft
1,271 measurements
Median tested yield
10 gpm
1,477 pump tests
Well depth
How deep are wells in Fallon County?
Of 1,760 wells with a recorded total depth, the median is 180 feet. Half were drilled between 82 and 400 feet; one in ten went deeper than 800 feet and one in ten found water shallower than 34 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
70 ft
median depth to water at rest · half between 30 and 120 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
10 gpm
median tested yield · half between 5 and 15 gpm
16% of tested wells produced under 5 gallons per minute and 22% 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 Fallon County
178 wells have been completed here since 2016, 6 of them in the last twelve months. The newest log on file was completed June 12, 2026. Records run back to 1900.
What the wells are for
- Stockwater1,481
- Domestic596
- Monitoring92
- Unused69
- Public Water Supply30
How they were drilled
- Rotary550
- Unknown469
- Forward Rotary233
- Drilled120
Drillers filing well logs in Fallon County
- Askin Drilling82 since 2016 · 2026
- Higgins Drilling Company41 since 2016 · 2026
- Haz Tech Drilling Inc16 since 2016 · 2021
- Montana Salinity Control Association16 since 2016 · 2025
- Hansen Environmental Drilling9 since 2016 · 2019
- H & H Drilling6 since 2016 · 2022
- Sharp Drilling Inc4 since 2016 · 2022
- Y-environmental4 since 2016 · 2017
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 Fallon County
Montana DNRC lists 3,946 water rights in the county: 1,702 groundwater and 2,244 surface water, 3,832 of them active. The median priority date is 1956, and the oldest claim dates to 1850.
Types of right
- Statement Of Claim2,933
- Ground Water Certificate680
- Provisional Permit185
- Stockwater Permit80
- Conservation District Record47
Purposes
- Stock2,633
- Irrigation446
- Domestic212
- Wildlife169
- Fish And Wildlife94
DNRC basins
- 42L2,332
- 39FJ724
- 42M292
- 39G237
- 39H234
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 Fallon 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.
- Fort Union Formation491 wells · 33% · median 120 ft
- Fox Hills-hell Creek Aquifer469 wells · 32% · median 500 ft
- Hell Creek Formation271 wells · 18% · median 260 ft
- Fox Hills Formation Or Sandstone176 wells · 12% · median 475 ft
- Alluvium (holocene)19 wells · 1% · median 20 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 Fallon County
Petroleum releases
23
10 open · 13 resolved
Superfund program sites
0
none on the National Priorities List
Registered tank facilities
43
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 2023. A property report screens the sites within a quarter, half and one mile of a specific parcel and links the agency records.