Private Well Water Testing in Connecticut
County-by-county USGS area-risk estimates for private wells across Connecticut — arsenic exceedance probability and private-well population — plus how to test your own well at a Connecticut-certified laboratory.
Connecticut private-well risk summary
Counties covered
9
Connecticut counties with modeled risk data.
People on private wells
area estimate673,887
estimated across covered Connecticut counties.
Average arsenic risk
area estimate8%
average modeled chance a well exceeds 10 µg/L arsenic across covered counties.
Connecticut counties
- Western Connecticut Planning Region7% arsenic exceedance (area estimate)146,132 people on private wells
- Capitol Planning Region10% arsenic exceedance (area estimate)134,179 people on private wells
- Naugatuck Valley Planning Region8% arsenic exceedance (area estimate)84,033 people on private wells
- Southeastern Connecticut Planning Region7% arsenic exceedance (area estimate)72,393 people on private wells
- Lower Connecticut River Valley Planning Region9% arsenic exceedance (area estimate)58,827 people on private wells
- South Central Connecticut Planning Region9% arsenic exceedance (area estimate)55,961 people on private wells
- Northwest Hills Planning Region4% arsenic exceedance (area estimate)54,546 people on private wells
- Northeastern Connecticut Planning Region9% arsenic exceedance (area estimate)53,203 people on private wells
- Greater Bridgeport Planning Region7% arsenic exceedance (area estimate)14,613 people on private wells
Find a Connecticut-certified testing lab
Get your well tested at a Connecticut-certified laboratory. We list certification programs by state.
Already tested your well? Get a free plain-English reading
Upload your well water lab report (PDF or a photo) and our team will email you a full, plain-English reading of every result — free. Educational only, never medical advice.
Your upload also helps us keep local water data accurate — we only ever share anonymized, area-level summaries.
Upload my well testThese 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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