Private Well Water Testing in Montana

County-by-county USGS area-risk estimates for private wells across Montana — arsenic exceedance probability and private-well population — plus how to test your own well at a Montana-certified laboratory.

Montana private-well risk summary

Counties covered

Montana counties with modeled risk data.

People on private wells

area estimate

280,212

estimated across covered Montana counties.

Average arsenic risk

area estimate

average modeled chance a well exceeds 10 µg/L arsenic across covered counties.

Montana counties

Find a Montana-certified testing lab

Get your well tested at a Montana-certified laboratory. We list certification programs by state.

Montana certified labs

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These figures are USGS area estimates: statistical groundwater models describing how likely elevated contaminant levels are across a county. They are not designed to predict the concentration in any single well. Only testing your own well reveals its water quality.

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By TapWaterData Editorial