State Well Water Guide
Tennessee Private Well Water Guide
About 22% of Tennesseans rely on private wells, primarily in rural east Tennessee mountain communities, middle Tennessee agricultural areas, and underserved rural west Tennessee communities. Tennessee's karst limestone geology — particularly the Central Basin's Nashville Dome — creates a highly permeable aquifer system vulnerable to surface contamination. East Tennessee's crystalline Appalachian geology produces natural arsenic risks. Agricultural contamination from livestock operations is the most pervasive statewide threat. TDEC regulates well construction but does not mandate ongoing testing.
Testing Guidance
TDEC recommends annual testing for coliform bacteria and nitrates. Middle Tennessee karst well owners should test quarterly for bacteria during the spring wet season given the rapid recharge pathways. East Tennessee Appalachian bedrock well owners should test for arsenic. West Tennessee sandy aquifer well owners should test for iron, manganese, and nitrates.
What to Test For in Tennessee
Total coliform bacteria and E. coli — annual minimum; quarterly for karst well owners
Nitrates — statewide agricultural areas, especially middle and west Tennessee
Arsenic — east Tennessee metamorphic and igneous rock wells
Iron and manganese — west Tennessee coastal plain aquifer wells
PFAS — near Arnold Air Force Base and other TN military facilities
Agricultural chemicals — karst areas adjacent to row crops and livestock operations
pH and hardness — karst well baseline chemistry
Common Contamination Risks in Tennessee
Karst aquifer vulnerability — much of middle Tennessee's groundwater flows through limestone conduits with minimal filtration; one of the state's most significant water quality challenges
Agricultural contamination from livestock — Tennessee's beef cattle, swine, and poultry industries contribute substantial nitrogen and pathogen loading to groundwater
Arsenic from east Tennessee Appalachian geology — the metamorphic and igneous rocks of the Ridge and Valley and Blue Ridge provinces contain natural arsenic
Iron and manganese in west Tennessee — shallow sandy aquifers in west TN naturally have elevated levels
Bacterial contamination from failing septic systems — rural Tennessee has high rates of aging and failing septic infrastructure
Contaminant Guides Relevant to TN 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
Find a Certified Lab in Tennessee
Use the Tennessee state-certified laboratory program to find accredited labs for private well testing. Always verify current certification before submitting samples.
TN Certified Lab Directory ↗Tennessee 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
TN Certified Labs ↗EPA guidance
EPA Private Wells Program ↗State lab directory
TN Certified Labs ↗Minimum Annual Tests
Plus state-specific contaminants listed above
Other State Guides