Methodology & sources

Every number on this site is computed from public records. This page shows the work.

Source data

All well records come from the Ground Water Information Center (GWIC) at the Montana Bureau of Mines and Geology — the state's official repository of well logs, where Montana drillers are required to file completion reports. We refresh our copy weekly from MBMG's public data service (272,443 active well records at last refresh, 2026-06-10). Each well in our reports links back to its original GWIC record.

Filters

• Site type WELL only (springs, test holes, and other site types excluded)
• Wells flagged abandoned are excluded from statistics
• Depth statistics use recorded total depths between 0 and 5,000 ft (sanity bound)
• Static water level statistics use measurements 0–2,000 ft below ground surface
• Yield statistics use pump-test results 0–5,000 gpm; where a well has multiple tests we use the maximum
• Counties with fewer than 10 records are not published

Statistics

We report medians and interquartile ranges (25th–75th percentile) rather than averages, because well data is heavily skewed — a few very deep wells would distort an average. "Recent" figures cover wells completed since 2016. Driller tables count wells by drilling_company on logs filed since 2016.

Cost estimates

We do not collect quotes. Cost ranges apply published national per-foot rates to the local median depth — the local depth is what makes the estimate useful, and it comes from actual drilled wells nearby:

• Drilling + casing: $25–$65 per foot
• Complete system (pump, pressure tank, hookup): $60–$110 per foot

Rate sources (last checked 2026-06-10):

• HomeGuide — Well Drilling Cost — national per-foot drilling and complete-system ranges
• Angi — How Much Does It Cost to Drill a Well? — cross-check for per-foot and component costs
• MBMG GWIC — all depth/static-water-level/yield figures are computed from GWIC records, not estimated

Estimates are planning figures, not quotes. Site access, geology, casing depth, and water treatment needs move real prices substantially.

Known data limitations

• Location accuracy varies: older records may be located to the nearest quarter-section (roughly ±0.5 miles).
• Not every well is registered — older and hand-dug wells are under-represented.
• GWIC notes that some records contain filing errors; we propagate the official record as filed.

Corrections

If a number here looks wrong, email us (or reply to any report). Confirmed errors are corrected and logged on the changelog. In this niche one wrong number costs more trust than ten missing features — we'd rather show less and be right.

About

Montana Well Data is an independent data publisher. We are not affiliated with MBMG, the State of Montana, or any drilling company. Revenue comes from property reports and from connecting homeowners with licensed local drillers — never from selling rankings or placements in the statistics.