Private wells
Tennessee well water: who's on a well and what to test for
People on private wells
859,800
Homes on wells
13.0%
Est. above arsenic limit
5,200
Every Tennessee county
Sorted by people on private wells. Arsenic and nitrate are modeled for typical wells in the county, not measured at yours; depth is the median of domestic well records.
| Wilson County | 49,900 | 33% | 3.7% | 0.5 | 147 ft |
| Anderson County | 32,700 | 44% | 2.5% | 0.2 | 187 ft |
| Sevier County | 27,900 | 29% | 2.8% | 0.2 | 255 ft |
| Coffee County | 25,100 | 45% | 1.7% | 1.3 | 80 ft |
| Knox County | 21,800 | 4% | 2.2% | 0.4 | 214 ft |
| Fayette County | 21,600 | 52% | 3.9% | 0.1 | 158 ft |
| Campbell County | 20,300 | 52% | 1.4% | 0.1 | 205 ft |
| Franklin County | 20,300 | 48% | 1.5% | 2.2 | 102 ft |
| Rutherford County | 19,700 | 6% | 1.5% | 0.7 | 170 ft |
| Williamson County | 18,500 | 8% | 1.3% | 0.4 | 180 ft |
| Blount County | 17,300 | 14% | 2.2% | 0.5 | 240 ft |
| Monroe County | 16,300 | 37% | 3.4% | 0.8 | 222 ft |
| McMinn County | 15,900 | 30% | 4.0% | 0.6 | 225 ft |
| Montgomery County | 15,900 | 6% | 1.3% | 1.2 | 155 ft |
| Jefferson County | 14,900 | 30% | 3.5% | 0.3 | 265 ft |
| Bradley County | 14,600 | 14% | 2.5% | 0.7 | 228 ft |
| Hawkins County | 14,500 | 27% | 6.1% | 0.3 | 245 ft |
| Hardeman County | 14,500 | 65% | 2.2% | 0.4 | 140 ft |
| Madison County | 14,300 | 15% | 2.1% | 0.5 | 135 ft |
| Cumberland County | 13,200 | 20% | 2.9% | 0.3 | 180 ft |
| Henry County | 13,000 | 40% | 1.8% | 0.5 | 105 ft |
| Loudon County | 12,800 | 26% | 1.5% | 0.6 | 280 ft |
| Washington County | 12,500 | 10% | 1.4% | 0.7 | 305 ft |
| Cocke County | 12,300 | 35% | 3.3% | 0.2 | 250 ft |
| Sullivan County | 11,500 | 7% | 2.4% | 0.3 | 263 ft |
| Gibson County | 11,400 | 23% | 2.6% | 0.4 | 140 ft |
| Fentress County | 11,200 | 59% | 2.8% | 0.3 | 160 ft |
| Weakley County | 11,000 | 34% | 2.7% | 0.1 | 130 ft |
| Lawrence County | 10,900 | 23% | 1.7% | 1.8 | 113 ft |
| Roane County | 10,800 | 20% | 1.6% | 0.1 | 225 ft |
| Sumner County | 10,100 | 5% | 2.0% | 1.4 | 95 ft |
| Humphreys County | 10,100 | 53% | 1.0% | 0.2 | 150 ft |
| Cheatham County | 9,800 | 25% | 2.4% | 0.3 | 160 ft |
| Hamilton County | 9,800 | 3% | 1.9% | 0.4 | 228 ft |
| Davidson County | 9,700 | 1% | 2.5% | 0.5 | 180 ft |
| Claiborne County | 9,500 | 29% | 1.3% | 0.2 | 265 ft |
| Carroll County | 9,000 | 34% | 2.2% | 0.4 | 125 ft |
| Grainger County | 9,000 | 39% | 2.3% | 0.2 | 300 ft |
| Benton County | 8,800 | 58% | 1.3% | 0.2 | 73 ft |
| Tipton County | 8,400 | 15% | 3.9% | 1.1 | 100 ft |
| Dickson County | 7,900 | 15% | 1.1% | 0.4 | 160 ft |
| Chester County | 7,800 | 47% | 2.7% | 0.4 | 125 ft |
| Marshall County | 7,700 | 22% | 1.9% | 0.7 | 175 ft |
| Carter County | 7,500 | 14% | 2.1% | 0.2 | 245 ft |
| Maury County | 7,200 | 8% | 1.6% | 0.6 | 186 ft |
| Marion County | 7,000 | 26% | 1.8% | 0.2 | 182 ft |
| Wayne County | 6,800 | 47% | 1.3% | 0.3 | 150 ft |
| Lincoln County | 6,700 | 19% | 1.7% | 1.6 | 82 ft |
| Scott County | 6,700 | 31% | 1.3% | 0.1 | 80 ft |
| Henderson County | 6,600 | 25% | 2.1% | 0.4 | 135 ft |
| Greene County | 6,500 | 10% | 3.4% | 0.6 | 265 ft |
| Giles County | 6,500 | 22% | 3.3% | 0.5 | 142 ft |
| Robertson County | 6,400 | 9% | 2.0% | 2.6 | 117 ft |
| Morgan County | 6,400 | 35% | 1.9% | 0.1 | 190 ft |
| Meigs County | 6,300 | 46% | 1.8% | 0.1 | 265 ft |
| Union County | 6,100 | 32% | 1.9% | 0.1 | 235 ft |
| Overton County | 6,000 | 27% | 1.7% | 1.1 | 150 ft |
| Stewart County | 6,000 | 46% | 1.2% | 0.1 | 180 ft |
| Polk County | 5,700 | 34% | 3.5% | 0.3 | 228 ft |
| Johnson County | 5,400 | 34% | 2.7% | 0.1 | 265 ft |
| Hickman County | 5,300 | 22% | 1.2% | 0.3 | 180 ft |
| Rhea County | 5,000 | 17% | 2.4% | 0.3 | 213 ft |
| Obion County | 4,800 | 15% | 4.1% | 0.2 | 109 ft |
| Sequatchie County | 4,800 | 31% | 2.2% | 0.2 | 225 ft |
| Bledsoe County | 4,600 | 37% | 2.4% | 0.4 | 220 ft |
| Haywood County | 4,500 | 26% | 3.3% | 0.2 | 130 ft |
| Cannon County | 4,500 | 31% | 3.0% | 0.7 | 97 ft |
| Lewis County | 4,000 | 33% | 1.2% | 0.2 | 145 ft |
| McNairy County | 4,000 | 15% | 1.5% | 0.2 | 125 ft |
| DeKalb County | 4,000 | 22% | 3.4% | 0.8 | 100 ft |
| Hamblen County | 4,000 | 7% | 2.7% | 0.5 | 245 ft |
| Macon County | 4,000 | 16% | 2.1% | 0.8 | 100 ft |
| Bedford County | 3,800 | 8% | 1.7% | 1.0 | 148 ft |
| Perry County | 3,800 | 46% | 1.5% | 0.1 | 125 ft |
| Warren County | 3,400 | 8% | 1.9% | 2.0 | 100 ft |
| Hancock County | 3,400 | 52% | 2.3% | 0.1 | 245 ft |
| Grundy County | 3,300 | 26% | 2.7% | 0.4 | 120 ft |
| Dyer County | 3,200 | 9% | 3.1% | 0.1 | 105 ft |
| Hardin County | 3,000 | 12% | 2.4% | 0.2 | 150 ft |
| Crockett County | 3,000 | 23% | 2.9% | 0.1 | 120 ft |
| Shelby County | 2,800 | 0% | 3.8% | 0.4 | 115 ft |
| Putnam County | 2,500 | 3% | 2.0% | 1.4 | 144 ft |
| Smith County | 2,400 | 13% | 2.9% | 0.4 | 118 ft |
| White County | 2,300 | 9% | 2.4% | 2.6 | 105 ft |
| Jackson County | 2,000 | 19% | 1.7% | 0.4 | 125 ft |
| Unicoi County | 1,900 | 12% | 2.1% | 0.1 | 225 ft |
| Decatur County | 1,800 | 17% | 1.8% | 0.4 | 100 ft |
| Clay County | 1,700 | 22% | 1.8% | 0.7 | 85 ft |
| Lauderdale County | 1,700 | 7% | 3.7% | 0.7 | 120 ft |
| Trousdale County | 1,600 | 19% | 2.3% | 0.5 | 103 ft |
| Van Buren County | 1,500 | 22% | 4.6% | 0.3 | 205 ft |
| Houston County | 1,300 | 17% | 1.2% | 0.3 | 160 ft |
| Moore County | 810 | 13% | 2.3% | 0.5 | 115 ft |
| Pickett County | 540 | 12% | 1.7% | 0.5 | n/a |
| Lake County | 250 | 6% | 2.7% | 0.1 | n/a |
Shading: red is among the highest counties nationally, amber the middle, green the lower range. Click a column to sort.
Most well users above the arsenic limit
- Hawkins County: about 770 people
- Sevier County: about 400 people
- Fayette County: about 360 people
- Grainger County: about 310 people
- Henry County: about 230 people
Test first, then treat what the test finds
We may earn a commission from links below, at no cost to you. Picks follow the testing order, not who pays. How we make money.
1. Certified lab well test
Start here, every year
A mail-in kit analyzed by a certified lab measures bacteria, nitrate, arsenic, metals and more. Test strips cannot measure arsenic or uranium reliably.
Mail-in certified lab well water test
Mid-range2. Sediment pre-filter
Sand, silt or cloudy water
A 5-micron cartridge after the pressure tank catches sand, silt and rust before they reach fixtures or other filters. Cartridges are cheap and swap every few months.
5-micron whole-house sediment filter
Budget3. Iron and sulfur filter
Orange stains or rotten-egg smell
Air-injection or oxidizing-media filters remove orange staining and rotten-egg smell. Size one from a lab result for iron, manganese and hydrogen sulfide.
Air-injection iron and sulfur filter
Premium4. UV disinfection system
Coliform bacteria in a test
Inactivates bacteria and viruses; usually for private wells or after boil notices.
12 GPM whole-house UV purifier
Premium5. Under-sink reverse osmosis
Arsenic, nitrate or uranium in a test
The most thorough option for drinking water: PFAS, lead, nitrate, arsenic and more. Look for NSF/ANSI 58.
Waterdrop G3P600 tankless RO
Price at Waterdrop, checked Oct 5, 2026or compare on Amazon
iSpring RCC7AK reverse osmosis
Mid-range6. Whole-house well filter
Several problems at once
Multi-stage sediment and carbon for every tap. Add UV if bacteria shows up, and choose stages from your lab results, not a guess.
Waterdrop WHF21 2-stage whole-house filter
Mid-rangeQuestions
Which Tennessee counties rely most on wells?+
By share of homes: Hardeman County (65%), Fentress County (59%), Benton County (58%), Humphreys County (53%), Hancock County (52%). By number of people: Wilson County (49,900), Anderson County (32,700), Sevier County (27,900).
Is arsenic a problem in Tennessee wells?+
USGS estimates about 5,200 Tennessee well users have water above the 10 microgram per liter arsenic limit that applies to public systems, the largest numbers in Hawkins County, Sevier County, Fayette County. Arsenic has no taste or smell, so only a lab test finds it.
Do I have to test my well when I sell a house in Tennessee?+
We could not confirm a statewide rule for Tennessee. Check with your county health department. Buyers can still make a lab test a condition of the offer.
How often should I test my well?+
No federal law covers private wells. EPA's drinking water limits apply to public water systems, so testing and treating a private well is up to the owner. EPA and CDC recommend testing at least once a year for coliform bacteria, nitrate, pH and total dissolved solids, and testing for arsenic, uranium, radon and other local concerns based on where you live.
Well-user counts, arsenic and nitrate figures are each a modeled estimate built from national datasets, not a count of tested wells, and well depths summarize drilling records rather than every well. Your own well can be very different from the county average, which is why the only answer for your home is a lab test. Sources: EPA Office of Research and Development, Water Source 2020 (private well estimates by census block); CDC Environmental Public Health Tracking, Well Water Index (from USGS nitrate and arsenic models); USGS, county-level domestic well population with arsenic above 10 micrograms per liter (Ayotte and others, 2017); USGS Synthesized Domestic Well Database for the Conterminous United States (SynDWell-US), McCarthy and others, 2025 (depth, where a county has 30+ usable records).