Montana water data · County
Madison County: well depth, groundwater and water rights
What the public record says about water in Madison 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 20,739 public records from MBMG GWIC, Montana DNRC, Montana DEQ, EPA SEMS, EPA UST Finder
Wells on record
6,775
6,499 with recorded depth
Median well depth
100 ft
half of wells 55–205 ft
Median static water level
32 ft
6,053 measurements
Median tested yield
22 gpm
6,007 pump tests
Well depth
How deep are wells in Madison County?
Of 6,499 wells with a recorded total depth, the median is 100 feet. Half were drilled between 55 and 205 feet; one in ten went deeper than 340 feet and one in ten found water shallower than 33 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 13 and 85 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
22 gpm
median tested yield · half between 15 and 35 gpm
4% of tested wells produced under 5 gallons per minute and 63% 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 Madison County
1,296 wells have been completed here since 2016, 101 of them in the last twelve months. The newest log on file was completed August 31, 2026. Records run back to 1863.
What the wells are for
- Domestic5,192
- Stockwater969
- Irrigation389
- Monitoring350
- Public Water Supply163
How they were drilled
- Rotary3,137
- Cable803
- Dual Rotary777
- Churn203
Drillers filing well logs in Madison County
- Graham Drilling Inc598 since 2016 · 2025
- Red Tiger Drilling164 since 2016 · 2026
- Potts Drilling Inc133 since 2016 · 2026
- Okeefe Drilling Co64 since 2016 · 2026
- Van Dyken Drilling Inc55 since 2016 · 2026
- Diamond M Drilling Inc36 since 2016 · 2025
- Ak Drilling Inc35 since 2016 · 2024
- Old Town Drilling35 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 Madison County
Montana DNRC lists 13,816 water rights in the county: 7,119 groundwater and 6,697 surface water, 12,564 of them active. The median priority date is 1930, and the oldest claim dates to 1856.
Types of right
- Statement Of Claim8,462
- Ground Water Certificate4,655
- Provisional Permit278
- Exempt Notice150
- Converted Terminates132
Purposes
- Stock4,455
- Irrigation3,288
- Domestic2,339
- Domestic; Lawn And Garden794
- Mining351
DNRC basins
- 41F5,168
- 41C4,264
- 41G2,867
- 41D765
- 41B513
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 Madison 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 Undifferentiated518 wells · 30% · median 97 ft
- Gneiss And Schist (early Proterozoic Or Archean)324 wells · 18% · median 220 ft
- Sand And Gravel (tertiary)182 wells · 10% · median 120 ft
- Sand And Gravel (pleistocene)130 wells · 7% · median 78 ft
- Sediments (tertiary)117 wells · 7% · median 101 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 Madison County
Petroleum releases
70
12 open · 58 resolved
Superfund program sites
2
none on the National Priorities List
Registered tank facilities
76
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 2019. A property report screens the sites within a quarter, half and one mile of a specific parcel and links the agency records.