State Well Water Guide
Kentucky Private Well Water Guide
Approximately 30% of Kentucky residents — about 1.3 million people — rely on private wells. Kentucky's geology creates one of the most complex well water situations in the nation: widespread karst limestone in the central and western parts of the state makes groundwater extremely vulnerable to rapid surface contamination, while eastern Kentucky's coal country adds legacy mining contamination including acid mine drainage, selenium, and iron. The Bluegrass region has naturally occurring elevated radon. Agricultural nitrate contamination is documented in multiple counties. The Kentucky Division of Water oversees well construction but does not mandate private well testing.
Testing Guidance
The Kentucky Division of Water and University of Kentucky Cooperative Extension recommend annual bacteria and nitrate testing for all private wells, with more frequent testing (every 6 months) recommended for karst areas given how rapidly contamination can enter the aquifer. Coal country wells in eastern Kentucky (Harlan, Letcher, Pike, Floyd, and Martin counties) should be tested for iron, manganese, sulfate, selenium, and pH. Radon testing is recommended for the Bluegrass region (Fayette, Woodford, Bourbon, and Scott counties). PFAS testing is warranted near Blue Grass Army Depot and Fort Campbell.
What to Test For in Kentucky
Total coliform bacteria and E. coli — annual minimum; more frequent in karst areas
Nitrates — annual for agricultural and horse farm areas
Iron, manganese, and sulfate — eastern Kentucky coal country wells
Selenium — coal mining areas; associated with Appalachian surface mining
pH — acidic drainage from coal mining can affect nearby wells
Radon — Bluegrass region's limestone and uranium-bearing geology
PFAS — wells near Blue Grass Army Depot (Richmond) and Fort Campbell
Volatile organic compounds (VOCs) — near gas stations, dry cleaners, or industrial sites
Common Contamination Risks in Kentucky
Karst vulnerability — Kentucky's limestone karst in the central and western regions allows rapid, direct contamination of groundwater from surface sources; Mammoth Cave National Park sits atop one of the most complex karst systems in the world
Coal mining legacy contamination — acid mine drainage, iron, manganese, and selenium in eastern Kentucky's Appalachian coalfields
Agricultural nitrate contamination — the Bluegrass horse farming region and western Kentucky row crops
Bacterial contamination post-flooding — Kentucky experiences significant flooding events that can compromise shallow wells
PFAS near military installations — Blue Grass Army Depot and Fort Campbell
Contaminant Guides Relevant to KY Wells
PFAS
Synthetic Chemicals
EPA limit: 4 ppt
Lead
Heavy Metals
EPA limit: 15 ppb (action level)
Nitrates
Agricultural Chemicals
EPA limit: 10 mg/L
DBPs
Disinfection Byproducts
EPA limit: 80 µg/L (TTHMs) / 60 µg/L (HAA5)
Arsenic
Heavy Metals
EPA limit: 10 ppb
Hard Water
Minerals
EPA limit: No federal limit
Chlorine
Disinfection Chemicals
EPA limit: 4 mg/L (MRDL)
Microplastics
Emerging Contaminants
EPA limit: No federal limit
Bacteria
Microbial Contamination
EPA limit: Zero E. coli / < 1 coliform per 100 mL
Fluoride
Minerals
EPA limit: 4 mg/L (MCL) / 2 mg/L (Secondary MCL)
Chromium-6
Heavy Metals
EPA limit: 100 ppb (total chromium)
Copper
Heavy Metals
EPA limit: 1.3 mg/L (action level)
Radon
Radioactive Contaminants
EPA limit: No finalized MCL
Iron & Manganese
Minerals
EPA limit: 0.3 mg/L iron / 0.05 mg/L manganese (aesthetic SMCLs)
Atrazine
Agricultural Chemicals
EPA limit: 3 ppb (0.003 mg/L)
Uranium
Radioactive Contaminants
EPA limit: 30 µg/L (30 ppb)
Perchlorate
Industrial Chemicals
EPA limit: 0.056 mg/L (56 ppb)
VOCs
Industrial Chemicals
EPA limit: Varies by compound: benzene 5 ppb; TCE 5 ppb; PCE 5 ppb; vinyl chloride 2 ppb
Radium
Radioactive Contaminants
EPA limit: 5 pCi/L (combined Ra-226 + Ra-228)
Crypto & Giardia
Microbial Contamination
EPA limit: Zero (treatment technique standard)
Hydrogen Sulfide
Naturally Occurring Compounds
EPA limit: No MCL; Secondary MCL (aesthetic) of 0.05 mg/L
Selenium
Minerals
EPA limit: 50 ppb (0.05 mg/L)
Cadmium
Heavy Metals
EPA limit: 5 ppb (0.005 mg/L)
Mercury
Heavy Metals
EPA limit: 2 ppb (0.002 mg/L)
Barium
Heavy Metals
EPA limit: 2 mg/L
pH
Water Quality Indicators
EPA limit: 6.5–8.5 (secondary standard)
Find a Certified Lab in Kentucky
Use the Kentucky state-certified laboratory program to find accredited labs for private well testing. Always verify current certification before submitting samples.
KY Certified Lab Directory ↗Kentucky Well Water FAQs
Related Pages
Data Sources & Provenance
All data on this page is sourced from official U.S. government or public datasets.
Quick Reference
State program
KY Certified Labs ↗EPA guidance
EPA Private Wells Program ↗State lab directory
KY Certified Labs ↗Minimum Annual Tests
Plus state-specific contaminants listed above
Other State Guides