Private wells · by county
Kentucky well water by county: arsenic and nitrate
Modelled arsenic and nitrate for private-well users in every Kentucky county, what to test for, and where to find a certified lab. Private wells aren’t covered by the Safe Drinking Water Act.
Kentucky counties
All 120 counties
- Pike CountyWell users 40,300Arsenic about 2 in 100Nitrate 0.0 mg/L
- Letcher CountyWell users 16,300Arsenic about 2 in 100Nitrate 0.0 mg/L
- Floyd CountyWell users 14,500Arsenic about 2 in 100Nitrate 0.0 mg/L
- Perry CountyWell users 14,000Arsenic about 2 in 100Nitrate 0.0 mg/L
- Whitley CountyWell users 13,900Arsenic about 2 in 100Nitrate 0.1 mg/L
- Harlan CountyWell users 13,500Arsenic about 1 in 100Nitrate 0.0 mg/L
- Knott CountyWell users 13,500Arsenic about 2 in 100Nitrate 0.0 mg/L
- Graves CountyWell users 12,300Arsenic about 2 in 100Nitrate 0.1 mg/L
- Calloway CountyWell users 12,000Arsenic about 2 in 100Nitrate 0.3 mg/L
- Hardin CountyWell users 10,900Arsenic about 1 in 100Nitrate 1.1 mg/L
- Johnson CountyWell users 10,700Arsenic about 2 in 100Nitrate 0.0 mg/L
- Clay CountyWell users 10,500Arsenic about 2 in 100Nitrate 0.0 mg/L
- Morgan CountyWell users 10,200Arsenic about 3 in 100Nitrate 0.0 mg/L
- Knox CountyWell users 10,000Arsenic about 2 in 100Nitrate 0.1 mg/L
- Lawrence CountyWell users 9,500Arsenic about 2 in 100Nitrate 0.0 mg/L
- Greenup CountyWell users 9,400Arsenic about 3 in 100Nitrate 0.1 mg/L
- Breathitt CountyWell users 8,900Arsenic about 2 in 100Nitrate 0.0 mg/L
- Meade CountyWell users 8,800Arsenic about 1 in 100Nitrate 1.6 mg/L
- Carter CountyWell users 8,400Arsenic about 2 in 100Nitrate 0.1 mg/L
- Casey CountyWell users 8,200Arsenic about 2 in 100Nitrate 0.4 mg/L
- Leslie CountyWell users 7,800Arsenic about 2 in 100Nitrate 0.0 mg/L
- Christian CountyWell users 7,700Arsenic about 1 in 100Nitrate 2.0 mg/L
- Magoffin CountyWell users 7,400Arsenic about 2 in 100Nitrate 0.0 mg/L
- Russell CountyWell users 7,400Arsenic about 2 in 100Nitrate 1.1 mg/L
- Grayson CountyWell users 7,300Arsenic about 2 in 100Nitrate 0.3 mg/L
- Bell CountyWell users 7,100Arsenic about 1 in 100Nitrate 0.0 mg/L
- Breckinridge CountyWell users 6,900Arsenic about 2 in 100Nitrate 0.4 mg/L
- Pulaski CountyWell users 6,800Arsenic about 2 in 100Nitrate 0.8 mg/L
- Adair CountyWell users 6,700Arsenic about 2 in 100Nitrate 1.1 mg/L
- Marshall CountyWell users 6,400Arsenic about 2 in 100Nitrate 0.6 mg/L
- McCracken CountyWell users 5,800Arsenic about 3 in 100Nitrate 0.2 mg/L
- Larue CountyWell users 5,600Arsenic about 2 in 100Nitrate 1.9 mg/L
- Bullitt CountyWell users 5,600Arsenic about 17 in 100Nitrate 0.3 mg/L
- Martin CountyWell users 5,600Arsenic about 2 in 100Nitrate 0.0 mg/L
- Laurel CountyWell users 5,300Arsenic about 2 in 100Nitrate 0.3 mg/L
- Allen CountyWell users 5,200Arsenic about 2 in 100Nitrate 1.2 mg/L
- Logan CountyWell users 5,200Arsenic about 2 in 100Nitrate 3.5 mg/L
- Elliott CountyWell users 5,000Arsenic about 2 in 100Nitrate 0.0 mg/L
- Lewis CountyWell users 5,000Arsenic about 5 in 100Nitrate 0.1 mg/L
- Wayne CountyWell users 5,000Arsenic about 2 in 100Nitrate 0.8 mg/L
- Barren CountyWell users 4,800Arsenic about 1 in 100Nitrate 2.5 mg/L
- Henderson CountyWell users 4,700Arsenic about 10 in 100Nitrate 0.5 mg/L
- Metcalfe CountyWell users 4,700Arsenic about 1 in 100Nitrate 1.2 mg/L
- Daviess CountyWell users 4,600Arsenic about 6 in 100Nitrate 0.5 mg/L
- Monroe CountyWell users 4,400Arsenic about 1 in 100Nitrate 1.3 mg/L
- Jefferson CountyWell users 4,300Arsenic about 11 in 100Nitrate 0.6 mg/L
- Wolfe CountyWell users 4,300Arsenic about 3 in 100Nitrate 0.0 mg/L
- Jackson CountyWell users 4,200Arsenic about 2 in 100Nitrate 0.1 mg/L
- Todd CountyWell users 4,000Arsenic about 2 in 100Nitrate 2.0 mg/L
- Hart CountyWell users 4,000Arsenic about 1 in 100Nitrate 0.8 mg/L
- Ballard CountyWell users 4,000Arsenic about 4 in 100Nitrate 0.2 mg/L
- Boyd CountyWell users 4,000Arsenic about 2 in 100Nitrate 0.1 mg/L
- McCreary CountyWell users 3,300Arsenic about 1 in 100Nitrate 0.1 mg/L
- Taylor CountyWell users 3,300Arsenic about 2 in 100Nitrate 2.0 mg/L
- Lincoln CountyWell users 3,200Arsenic about 3 in 100Nitrate 0.8 mg/L
- Carlisle CountyWell users 2,900Arsenic about 3 in 100Nitrate 0.1 mg/L
- Caldwell CountyWell users 2,900Arsenic about 2 in 100Nitrate 0.4 mg/L
- Nelson CountyWell users 2,900Arsenic about 11 in 100Nitrate 1.4 mg/L
- Livingston CountyWell users 2,900Arsenic about 2 in 100Nitrate 0.1 mg/L
- Crittenden CountyWell users 2,700Arsenic about 3 in 100Nitrate 0.1 mg/L
- Hickman CountyWell users 2,700Arsenic about 4 in 100Nitrate 0.1 mg/L
- Webster CountyWell users 2,600Arsenic about 5 in 100Nitrate 0.3 mg/L
- Clinton CountyWell users 2,600Arsenic about 2 in 100Nitrate 1.5 mg/L
- Ohio CountyWell users 2,600Arsenic about 4 in 100Nitrate 0.3 mg/L
- Green CountyWell users 2,500Arsenic about 1 in 100Nitrate 1.6 mg/L
- Rowan CountyWell users 2,300Arsenic about 3 in 100Nitrate 0.1 mg/L
- Hancock CountyWell users 2,000Arsenic about 2 in 100Nitrate 0.3 mg/L
- Owsley CountyWell users 2,000Arsenic about 2 in 100Nitrate 0.0 mg/L
- Lyon CountyWell users 1,900Arsenic about 2 in 100Nitrate 0.3 mg/L
- Butler CountyWell users 1,900Arsenic about 5 in 100Nitrate 0.5 mg/L
- Trigg CountyWell users 1,800Arsenic about 1 in 100Nitrate 0.7 mg/L
- Rockcastle CountyWell users 1,800Arsenic about 4 in 100Nitrate 0.2 mg/L
- Menifee CountyWell users 1,700Arsenic about 3 in 100Nitrate 0.1 mg/L
- Lee CountyWell users 1,700Arsenic about 3 in 100Nitrate 0.0 mg/L
- Fleming CountyWell users 1,700Arsenic about 7 in 100Nitrate 0.9 mg/L
- Hopkins CountyWell users 1,600Arsenic about 5 in 100Nitrate 0.3 mg/L
- Washington CountyWell users 1,600Arsenic about 1 in 100Nitrate 2.2 mg/L
- Bath CountyWell users 1,500Arsenic about 8 in 100Nitrate 0.9 mg/L
- Powell CountyWell users 1,500Arsenic about 3 in 100Nitrate 0.1 mg/L
- Shelby CountyWell users 1,500Arsenic about 4 in 100Nitrate 3.4 mg/L
- Union CountyWell users 1,500Arsenic about 19 in 100Nitrate 0.4 mg/L
- Clark CountyWell users 1,400Arsenic about 2 in 100Nitrate 1.2 mg/L
- Boone CountyWell users 1,400Arsenic about 5 in 100Nitrate 0.5 mg/L
- Warren CountyWell users 1,300Arsenic about 2 in 100Nitrate 3.2 mg/L
- Edmonson CountyWell users 1,300Arsenic about 2 in 100Nitrate 0.9 mg/L
- Bourbon CountyWell users 1,300Arsenic about 2 in 100Nitrate 1.6 mg/L
- Cumberland CountyWell users 1,200Arsenic about 2 in 100Nitrate 0.2 mg/L
- McLean CountyWell users 1,200Arsenic about 8 in 100Nitrate 0.6 mg/L
- Muhlenberg CountyWell users 1,200Arsenic about 4 in 100Nitrate 0.7 mg/L
- Madison CountyWell users 1,200Arsenic about 2 in 100Nitrate 0.9 mg/L
- Marion CountyWell users 1,200Arsenic about 2 in 100Nitrate 2.1 mg/L
- Scott CountyWell users 1,100Arsenic about 2 in 100Nitrate 1.0 mg/L
- Estill CountyWell users 1,100Arsenic about 3 in 100Nitrate 0.2 mg/L
- Montgomery CountyWell users 1,000Arsenic about 4 in 100Nitrate 0.9 mg/L
- Oldham CountyWell users 1,000Arsenic about 10 in 100Nitrate 1.2 mg/L
- Boyle CountyWell users 990Arsenic about 1 in 100Nitrate 2.1 mg/L
- Mercer CountyWell users 940Arsenic about 2 in 100Nitrate 2.4 mg/L
- Henry CountyWell users 920Arsenic about 5 in 100Nitrate 1.6 mg/L
- Owen CountyWell users 910Arsenic about 4 in 100Nitrate 0.5 mg/L
- Spencer CountyWell users 900Arsenic about 4 in 100Nitrate 1.8 mg/L
- Kenton CountyWell users 890Arsenic about 7 in 100Nitrate 0.5 mg/L
- Campbell CountyWell users 870Arsenic about 5 in 100Nitrate 0.6 mg/L
- Fulton CountyWell users 860Arsenic about 5 in 100Nitrate 0.1 mg/L
- Jessamine CountyWell users 800Arsenic about 3 in 100Nitrate 1.8 mg/L
- Nicholas CountyWell users 790Arsenic about 3 in 100Nitrate 1.0 mg/L
- Fayette CountyWell users 790Arsenic about 2 in 100Nitrate 2.1 mg/L
- Grant CountyWell users 780Arsenic about 4 in 100Nitrate 0.4 mg/L
- Garrard CountyWell users 770Arsenic about 3 in 100Nitrate 1.1 mg/L
- Anderson CountyWell users 750Arsenic about 3 in 100Nitrate 0.6 mg/L
- Mason CountyWell users 710Arsenic about 2 in 100Nitrate 1.6 mg/L
- Woodford CountyWell users 660Arsenic about 3 in 100Nitrate 2.4 mg/L
- Franklin CountyWell users 640Arsenic about 5 in 100Nitrate 0.9 mg/L
- Simpson CountyWell users 610Arsenic about 2 in 100Nitrate 5.2 mg/L
- Gallatin CountyWell users 600Arsenic about 5 in 100Nitrate 0.5 mg/L
- Harrison CountyWell users 570Arsenic about 2 in 100Nitrate 1.0 mg/L
- Trimble CountyWell users 510Arsenic about 3 in 100Nitrate 0.8 mg/L
- Carroll CountyWell users 470Arsenic about 5 in 100Nitrate 0.6 mg/L
- Pendleton CountyWell users 470Arsenic about 5 in 100Nitrate 0.3 mg/L
- Bracken CountyWell users 440Arsenic about 2 in 100Nitrate 0.5 mg/L
- Robertson CountyWell users 190Arsenic about 2 in 100Nitrate 0.4 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
What the model can and can’t tell you
- 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.
What to test your well for
- 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
Where to test in Kentucky
Use a state-certified lab
Kentucky Department for Environmental Protection lists the laboratories certified to test drinking water in Kentucky.
Commercial · test your own well
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.
Questions
Kentucky 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 Kentucky?
About 532,700 people across 120 Kentucky counties, by the USGS 2010 estimate. USGS models place about 14,300 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 Kentucky?
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 Kentucky?
Kentucky Department for Environmental Protection keeps the list of laboratories certified to test drinking water in Kentucky. Only use laboratories that are certified to do drinking water testing. (EPA)