Well water in Kansas

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Testing strongly recommended

tested well samples in Kansas exceeded the EPA limit for nitrate (10 mg/L), based on public data from USGS Water Quality Portal and Kansas Geological Survey groundwater quality samples.

121,337 test results across 15 contaminants from at least 8,520 wells, 1913 to 2026; nitrate has the most at 23,190. Data refreshed September 15, 2026.

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

These are KGS and groundwater management district sampling wells, not a survey of homeowners' wells.

An estimated 149,282 people in Kansas get their drinking water from a private well, per USGS 2015 county water use.

Separately, the USGS national arsenic model estimates that 4% of the 149,282 people on private wells in Kansas draw water above 10 ug/L (the model's range is 3% to 5%), from geology and well depth rather than local tests.

What individual samples found

Each row summarizes every public sample for that contaminant inside Kansas. 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
Nitrate 1923 to 2026	21%	23,190	84%	2	2,030	10 mg/L EPA limit
Arsenic 1976 to 2024	16%	5,192	74%	2.6	243	10 ug/L EPA limit
Uranium 1977 to 2024	3%	315	93%	3.94	75.6	30 ug/L EPA limit
Radium (226 + 228) 1977 to 2021	3%	318	92%	0.245	23	5 pCi/L EPA limit
E. coli 2000 to 2026	2%	2,128	2%	0	14,000	0 MPN/100mL EPA limit
Copper 1976 to 2024	1%	2,984	35%	0	110	1.3 mg/L EPA limit
Lead 1976 to 2024	<1%	2,774	31%	0	2,600	15 ug/L EPA limit
Fluoride 1923 to 2024	<1%	17,657	100%	0.4	16	4 mg/L EPA limit
Chloride 1913 to 2024	no limit	22,333	99%	41	160,000	250 mg/L nuisance level
Sodium 1913 to 2024	no limit	17,995	100%	46	80,000	20 mg/L health guideline
Iron 1913 to 2024	no limit	15,793	85%	150	177,000	300 ug/L nuisance level
Manganese 1938 to 2024	no limit	10,500	84%	160	11,000	300 ug/L health guideline
Radon 1990 to 2018	no limit	140	99%	370	3,100	2,000 pCi/L health guideline

Sampled fewer than 10 times, too few to summarize: PFOS (9), PFOA (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	25%16,666 samples	9%4,246 samples	12%2,165 samples	14%113 samples
Fluoride	<1%14,325 samples	<1%2,127 samples	0%1,186 samples	0%19 samples
Arsenic	10%1,927 samples	21%2,056 samples	18%1,190 samples	0%19 samples
Copper	<1%1,236 samples	0%858 samples	3%876 samples	43%14 samples
Lead	2%1,186 samples	0%856 samples	0%722 samples	0%10 samples
E. coli	n/a	3%279 samples	<1%1,796 samples	43%53 samples

E. coli above the limit in Kansas rose from <1% of 1796 samples in the 2010s to 43% of 53 in the 2020s.

Nitrate, fluoride, arsenic, copper, lead have held within a few points between the two most recent periods with enough samples.

What this means

The contaminants most often above their limit here are nitrate (21% of 23,190 samples), arsenic (16% of 5,192 samples), and uranium (3% of 315 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 Kansas

1
Nitrate
21% of 23,190 local samples were above the limit.
2
Arsenic
16% of 5,192 local samples were above the limit.
3
Uranium
3% of 315 local samples were above the limit.
4
Radium (226 + 228)
3% of 318 local samples were above the limit.
5
E. coli
2% of 2,128 local samples were above the limit.
6
Copper
1% of 2,984 local samples were above the limit.
7
Lead
<1% of 2,774 local samples were above the limit.
8
Volatile organic compounds (VOCs)
11,919 leaking underground storage tank sites on record locally.
9
Metals panel
106 hazardous waste sites on record locally.

Test your Kansas well for nitrate, arsenic and uranium

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 Kansas: certified labs, state programs and prices.

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

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Send me the Kansas report

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

The rock under Kansas

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.

Contamination sources on record in Kansas

KDHE records 11,919 leaking underground storage tank sites and 106 hazardous waste sites in Kansas, among 16,748 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.

11,919: leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
106: hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
3,679: other remediation projects
1,044: other solid waste facilities

Treatment that fits the local profile

Nitrate

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

Arsenic

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

Uranium

Point-of-use reverse osmosis; Anion exchange; Whole-house anion exchange

Radium (226 + 228)

Water softener (cation exchange); Point-of-use reverse osmosis

E. coli

Shock chlorination and fix the well cap or casing; UV disinfection whole-house; Chlorination system

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 nitrate

Under-sink reverse osmosis system

under-sink or countertop, about $300

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

For nitrate

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 E. coli

UV disinfection system

whole-house, at the point of entry, about $900

Fix the well cap and casing first; UV keeps bacteria from returning.

For E. coli

Aquasana Rhino Well Water with UV

whole-house, at the point of entry, about $2,871

Whole-house system built for wells: sediment pre-filter, KDF and carbon, and a UV lamp rated to kill 99.99% of bacteria and viruses. It does not remove arsenic, nitrate, uranium or radon.

For copper

Acid neutralizing filter

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

Raises pH so plumbing stops leaching lead and copper.

Common questions

Is there arsenic in well water in Kansas?

Arsenic was detected in 74% of 5,192 public well samples in Kansas, and 16% 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 high is radon in well water in Kansas?

The median radon level across 140 public samples in Kansas was 370 pCi/L, with a high of 3,100 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.

How often should I test a private well in Kansas?

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 Kansas

2 counties have fewer than 30 public samples and are included in the Kansas totals above rather than shown separately: Wilson, Woodson.

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

Sources

USGS Water Quality Portal: 120,965 samples in Kansas. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
Kansas Geological Survey groundwater quality samples: 372 samples in Kansas. Groundwater quality samples from the Kansas Geological Survey and Groundwater Management District 2, joined to WWC5 well records. Retrieved September 9, 2026.
USGS national arsenic model (Ayotte 2017): estimated share of 149,282 people on private wells in Kansas 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.
KDHE regulated sites: 16,748 regulated sites located in Kansas. Identified contaminated sites, leaking underground storage tank facilities and solid waste facilities from the Kansas Department of Health and Environment. Retrieved September 9, 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.