Vermont well water by county: arsenic and nitrate
Modelled arsenic and nitrate for private-well users in every Vermont county, what to test for, and where to find a certified lab. Private wells aren’t covered by the Safe Drinking Water Act.
All 14 counties
- Windsor CountyWell users 24,300Arsenic about 8 in 100Nitrate 0.0 mg/L
- Chittenden CountyWell users 24,100Arsenic about 5 in 100Nitrate 0.1 mg/L
- Windham CountyWell users 22,700Arsenic about 7 in 100Nitrate 0.0 mg/L
- Rutland CountyWell users 21,300Arsenic about 4 in 100Nitrate 0.1 mg/L
- Washington CountyWell users 17,800Arsenic about 5 in 100Nitrate 0.0 mg/L
- Franklin CountyWell users 15,900Arsenic about 6 in 100Nitrate 0.1 mg/L
- Orange CountyWell users 15,600Arsenic about 6 in 100Nitrate 0.0 mg/L
- Addison CountyWell users 15,600Arsenic about 4 in 100Nitrate 0.0 mg/L
- Bennington CountyWell users 13,900Arsenic about 2 in 100Nitrate 0.1 mg/L
- Lamoille CountyWell users 10,600Arsenic about 5 in 100Nitrate 0.1 mg/L
- Caledonia CountyWell users 10,500Arsenic about 4 in 100Nitrate 0.0 mg/L
- Orleans CountyWell users 9,900Arsenic about 6 in 100Nitrate 0.0 mg/L
- Essex CountyWell users 2,100Arsenic about 4 in 100Nitrate 0.0 mg/L
- Grand Isle CountyWell users 2,100Arsenic about 6 in 100Nitrate 0.0 mg/L
Each mark = 1 in 100 well users the model places above 10 µg/L arsenic (scale 0–10)10 mg/L nitrate: the federal limit (MCL) for public systems
- These figures describe the area, not your well. Only a lab test shows what’s in your water.
- CDC says the Well Water Index figures “do not describe risk to individual wells.” (CDC Tracking Network)
- The arsenic model is better at spotting low-arsenic areas than at confirming high ones.
- Well-user counts are 2010 USGS estimates; tract values are averages over each census tract.
- Total coliform bacteriaEvery year
- NitrateEvery year
- Total dissolved solidsEvery year
- pHEvery year
- ArsenicAsk your local health department
EPA: Private Drinking Water Wells · CDC: Guidelines for Testing Well Water
Use a state-certified lab
Vermont Department of Health lists the laboratories certified to test drinking water in Vermont.
Screening tells you if something is worth a closer look
A lab result is the number you can act on.
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Lab-certified results
ETR Labs Basic Water Quality Test Kit
ETR Laboratories
50+ substances, including lead, copper, arsenic, nitrate, hardness and coliform bacteria
- Analyzed by Environmental Testing and Research Laboratories (ETR Labs), Leominster, MA · ISO/IEC 17025:2017, ANAB certificate AT-2638
- Turnaround: 2–4 business days after the lab receives it
What it can't tell you: It does not test PFAS, and not every result on the panel falls under the lab's accredited scope.
Screening: quick check, not lab-grade
Watersafe Drinking Water Test Kit
Silver Lake Research
Lead, bacteria, nitrate, copper, iron, chlorine, hardness and pH
- Turnaround: Minutes; the bacteria test can take up to 48 hours
What it can't tell you: Each test gives a yes/no or a rough range, not a lab number, and it cannot detect PFAS or arsenic.
A mail-in kit’s lab is accredited (ISO/IEC 17025) but may not be certified by your state. For a home sale, a loan, or a health-department follow-up, use a state-certified lab.
Vermont well water
Sources: CDC Well Water Index (2024) · USGS arsenic and nitrate models · USGS domestic well populations · EPA and CDC testing guidance. Data last updated 2026-10-08. All sources →
How many people use private wells in Vermont?
About 206,200 people across 14 Vermont counties, by the USGS 2010 estimate. USGS models place about 11,000 of them in areas where wells are likely to be above the 10 µg/L arsenic limit. These are area estimates, not well results.
Are private wells regulated in Vermont?
The quality and safety of drinking water from private domestic wells are not regulated by the Federal Government under the Safe Drinking Water Act nor by most state governments and laws. (EPA) Testing and treatment are the owner's responsibility.
Where can I get my well tested in Vermont?
Vermont Department of Health keeps the list of laboratories certified to test drinking water in Vermont. Only use laboratories that are certified to do drinking water testing. (EPA)