Private Well Water Testing in Illinois

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

Illinois private-well risk summary

Counties covered

102

Illinois counties with modeled risk data.

People on private wells

area estimate

1,120,033

estimated across covered Illinois counties.

Average arsenic risk

area estimate

12%

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

Illinois counties

Find a Illinois-certified testing lab

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

Illinois 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