Well water in Kentucky

Name: Private well water quality in Kentucky
Creator: Well Water Nerd
License: Public domain (US federal government data)

1in6

Testing recommended

tested well samples in Kentucky exceeded the EPA limit for lead (15 ug/L), based on public data from USGS Water Quality Portal.

16,186 test results across 15 contaminants from at least 2,135 wells, 1906 to 2024; nitrate has the most at 3,270. Data refreshed September 15, 2026.

Compiled by Nick at Well Water Nerd from public records. How these pages are built

An estimated 440,663 people in Kentucky get their drinking water from a private well, per USGS 2015 county water use.

Separately, the USGS national arsenic model estimates that 2% of the 440,663 people on private wells in Kentucky draw water above 10 ug/L (the model's range is 1% to 2%), from geology and well depth rather than local tests.

What individual samples found

Each row summarizes every public sample for that contaminant inside Kentucky. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.

Contaminant	Above limit	Samples	Detected	Median	Highest	Limit
Lead 1962 to 2019	16%	198	37%	0	46	15 ug/L EPA limit
Nitrate 1944 to 2019	10%	3,270	95%	0.4	439	10 mg/L EPA limit
Arsenic 1974 to 2019	2%	112	15%	0	24	10 ug/L EPA limit
Fluoride 1944 to 2019	2%	2,963	99%	0.2	78	4 mg/L EPA limit
Copper 1952 to 2019	0%	207	48%	0	0.065	1.3 mg/L EPA limit
Uranium 1955 to 2019	0%	34	41%	0	2.88	30 ug/L EPA limit
Radium (226 + 228) 2013 to 2019	0%	19	42%	0	1.2	5 pCi/L EPA limit
E. coli 2013 to 2019	0%	10	0%	0	0	0 MPN/100mL EPA limit
Chloride 1928 to 2024	no limit	3,123	99%	16	205,000	250 mg/L nuisance level
Iron 1928 to 2019	no limit	2,768	98%	460	9,700,000	300 ug/L nuisance level
Sodium 1906 to 2019	no limit	1,852	100%	18	67,700	20 mg/L health guideline
Manganese 1944 to 2019	no limit	1,607	96%	90	420,000	300 ug/L health guideline

Sampled fewer than 10 times, too few to summarize: PFOA (7), PFOS (7), Radon (9).

Over time

Share of samples above the limit by period. A cell needs ten samples to show; a comparison needs twenty in each period. Later periods sample fewer wells, and often the ones already known to have a problem.

Contaminant	before 2000	2000s	2010s	2020s
Nitrate	10%3,250 samples	n/a	5%20 samples	n/a
Fluoride	2%2,941 samples	0%12 samples	0%10 samples	n/a
Copper	0%196 samples	n/a	0%11 samples	n/a
Lead	17%187 samples	n/a	0%11 samples	n/a
Arsenic	0%89 samples	8%12 samples	9%11 samples	n/a
Uranium	0%23 samples	n/a	0%11 samples	n/a

Nitrate above the limit in Kentucky fell from 10% of 3250 samples before 2000 to 5% of 20 in the 2010s.

What this means

The contaminants most often above their limit here are lead (16% of 198 samples), nitrate (10% of 3,270 samples), and arsenic (2% of 112 samples). A well next door can differ sharply from yours because bedrock fractures, well depth and plumbing all matter, so these rates describe the area, not your tap.

Chloride, Iron, and Manganese are widespread in local groundwater. They are mainly a staining and taste problem, but high manganese also carries a health advisory for infants.

What to test for in Kentucky

1
Lead
16% of 198 local samples were above the limit.
2
Nitrate
10% of 3,270 local samples were above the limit.
3
Arsenic
2% of 112 local samples were above the limit.
4
Fluoride
2% of 2,963 local samples were above the limit.
5
Coliform bacteria
Recommended for every private well, every year.
6
Radon
Median local reading is 290 pCi/L.
7
PFOA
Above the limit in 2 of 7 local samples; too few to quote a rate.

Test your Kentucky well for lead, nitrate and arsenic

Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.

Order the Tap Score well water test kit, from $209 Already tested? Upload the report

Just want bacteria checked first? Tap Score coliform and E. coli test, $99. Coliform and E. coli are the tests every well needs every year.

Want a quick look before paying for a lab? Home well water test strips on Amazon check hardness, iron, pH and nitrate in minutes. They are a screen, not a result: arsenic, bacteria, uranium and PFAS need a certified lab.

Affiliate links: the merchant pays us a commission and the price is the same for you. It does not change what the data above says. As an Amazon Associate we earn from qualifying purchases.

Where to get a well tested in Kentucky: certified labs, state programs and prices.

Already have results back? Get your lab report read against the Kentucky numbers, $29. Every line explained, ranked by what matters, with the fix for each.

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Send me the Kentucky report

The numbers above, which tests to order and where, and the treatment that fits the local profile, in one email.

The rock under Kentucky

Not a principal aquifer

The USGS map places this area outside any principal aquifer, which usually means wells here draw from fractured bedrock or thin local deposits rather than a large regional aquifer. Bedrock wells of that kind are where arsenic, radon and uranium turn up, and yields vary from well to well.

Classification from the USGS Principal Aquifers of the United States (national map, 2003 edition, GIS release 2015), read at the state centroid. A single well can sit in a different unit, especially near a boundary.

Official help in Kentucky

Two places to start that are not selling anything: the state program that answers private well questions, and its list of labs certified to run drinking water tests. A certified lab is the difference between a result you can act on and a number.

Water Well Information, Kentucky Energy and Environment Cabinet
Drinking Water Lab Certification Program, Kentucky Energy and Environment Cabinet

Contamination sources on record in Kentucky

Kentucky waste landfill facilities records 29 regulated sites in Kentucky, among 29 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.

29: lined landfills and transfer facilities

Treatment that fits the local profile

Lead

Point-of-use reverse osmosis; Certified lead-removal carbon filter; Neutralizing filter to raise pH and stop leaching

Nitrate

Point-of-use reverse osmosis; Anion exchange; Distillation

Arsenic

Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange

Fluoride

Point-of-use reverse osmosis; Activated alumina; Distillation

Chloride

Point-of-use reverse osmosis; Distillation

Systems we would look at first

Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.

For lead

Under-sink reverse osmosis system

under-sink or countertop, about $300

Look for NSF/ANSI 58 certification listing the contaminant you need removed.

For lead

Acid neutralizing filter

whole-house, at the point of entry, about $1,200

Raises pH so plumbing stops leaching lead and copper.

For lead

Aquasana SmartFlow reverse osmosis

under-sink or countertop, about $225

Certified to NSF/ANSI 58 and 53 to reduce arsenic (96%, pentavalent), fluoride (90%), lead (99%), nitrate, nitrite and PFOA/PFOS at the kitchen tap, with a remineralizer.

For arsenic

Whole-house arsenic and uranium filter

whole-house, at the point of entry, about $2,500

Adsorptive iron-based media; sized to your well yield.

For iron

Iron and manganese oxidizing filter

whole-house, at the point of entry, about $1,800

Air-injection or greensand media; fixes staining at the source.

Common questions

Is there arsenic in well water in Kentucky?

Arsenic was detected in 15% of 112 public well samples in Kentucky, and 2% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.

How often should I test a private well in Kentucky?

Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.

Counties in Kentucky

Want the numbers themselves? Download the Kentucky dataset as CSV, every county and town, with the sources named.

Sources

USGS Water Quality Portal: 16,186 samples in Kentucky. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
USGS national arsenic model (Ayotte 2017): estimated share of 440,663 people on private wells in Kentucky above 10 ug/L of arsenic, from geology, well depth and land use. County estimates of domestic well users with arsenic above 10 ug/L from the USGS national logistic regression model (Ayotte, Medalie and Qi, 2017), with private well population from the USGS 2015 county water-use compilation (Dieter and others, 2018). Retrieved September 15, 2026.
Kentucky waste landfill facilities: 29 regulated sites located in Kentucky. Permitted landfill facilities from the Kentucky Energy and Environment Cabinet. Retrieved September 18, 2026.

Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.