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Montana water data · County

Gallatin County: well depth, groundwater and water rights

What the public record says about water in Gallatin 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 44,763 public records from MBMG GWIC, Montana DNRC, Montana DEQ, EPA SEMS, EPA UST Finder

Wells on record

20,270

19,389 with recorded depth

Median well depth

80 ft

half of wells 55–155 ft

Median static water level

27 ft

18,579 measurements

Median tested yield

30 gpm

18,480 pump tests

Well depth

How deep are wells in Gallatin County?

Of 19,389 wells with a recorded total depth, the median is 80 feet. Half were drilled between 55 and 155 feet; one in ten went deeper than 280 feet and one in ten found water shallower than 37 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.

under 50 ft
21%
50–100 ft
36%
100–200 ft
24%
200–300 ft
9%
300–500 ft
6%
500 ft and deeper
3%

Static water level

27 ft

median depth to water at rest · half between 12 and 60 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

30 gpm

median tested yield · half between 20 and 50 gpm

3% of tested wells produced under 5 gallons per minute and 78% 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 Gallatin County

3,059 wells have been completed here since 2016, 211 of them in the last twelve months. The newest log on file was completed September 11, 2026. Records run back to 1860.

What the wells are for

  • Domestic15,254
  • Irrigation2,162
  • Stockwater1,489
  • Monitoring1,179
  • Public Water Supply595

How they were drilled

  • Rotary12,490
  • Cable2,495
  • Forward Rotary881
  • Churn570

Drillers filing well logs in Gallatin County

  • Potts Drilling Inc779 since 2016 · 2026
  • Van Dyken Drilling Inc576 since 2016 · 2026
  • Red Tiger Drilling501 since 2016 · 2026
  • Bridger Drilling Inc477 since 2016 · 2026
  • Diamond M Drilling Inc302 since 2016 · 2026
  • Okeefe Drilling Co109 since 2016 · 2026
  • Old Town Drilling71 since 2016 · 2026
  • Western Water Wells59 since 2016 · 2026

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 Gallatin County

Montana DNRC lists 23,959 water rights in the county: 17,882 groundwater and 6,077 surface water, 21,245 of them active. The median priority date is 1984, and the oldest claim dates to 1858.

Types of right

  • Ground Water Certificate13,217
  • Statement Of Claim9,172
  • Provisional Permit762
  • Exempt Notice372
  • Converted Terminates227

Purposes

  • Domestic6,305
  • Stock4,288
  • Irrigation3,544
  • Domestic; Lawn And Garden3,189
  • Lawn And Garden816

DNRC basins

  • 41H19,982
  • 41F1,626
  • 41I913
  • 43A885
  • 41G513

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 Gallatin 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.

  • Cenozoic Undifferentiated892 wells · 31% · median 103 ft
  • Sediments (tertiary)262 wells · 9% · median 163 ft
  • Alluvium (quaternary)242 wells · 8% · median 47 ft
  • Alluvium (pleistocene)145 wells · 5% · median 111 ft
  • Gneiss And Schist (early Proterozoic Or Archean)134 wells · 5% · median 300 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 Gallatin County

Petroleum releases

228

11 open · 217 resolved

Superfund program sites

2

1 on or proposed for the NPL

Registered tank facilities

304

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 2025. A property report screens the sites within a quarter, half and one mile of a specific parcel and links the agency records.