Marion: well depth, groundwater and water rights

Well depth

How deep are wells in Marion?

Of 431 wells with a recorded total depth, the median is 198 feet. Half were drilled between 78 and 340 feet; one in ten went deeper than 502 feet and one in ten found water shallower than 50 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.

Drilling activity

Recent well drilling in Marion

133 wells have been completed here since 2016, 16 of them in the last twelve months. The newest log on file was completed September 30, 2026. Records run back to 1920.

Water rights

Water rights on file in Marion

Montana DNRC lists 279 water rights with a point of diversion inside this area: 264 groundwater and 15 surface water, 263 of them active. The median priority date is 2003, and the oldest claim dates to 1900.

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 Marion 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.

• Alluvium (holocene)54 wells · 40% · median 50 ft
• Ravalli Group32 wells · 24% · median 304 ft
• Alluvium (pleistocene)14 wells · 10% · median 153 ft
• Belt Supergroup13 wells · 10% · median 397 ft
• Glacial Outwash (pleistocene)11 wells · 8% · median 84 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 Marion

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 2022. A property report screens the sites within a quarter, half and one mile of a specific parcel and links the agency records.