Well water in Indiana

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

1in7

Testing recommended

tested well samples in Indiana exceeded the EPA limit for arsenic (10 ug/L), based on public data from USGS Water Quality Portal.

32,909 test results across 15 contaminants from at least 3,703 wells, 1901 to 2026; chloride has the most at 6,616. Data refreshed September 15, 2026.

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

An estimated 1,677,339 people in Indiana get their drinking water from a private well, per USGS 2015 county water use.

Separately, the USGS national arsenic model estimates that 9% of the 1,677,339 people on private wells in Indiana draw water above 10 ug/L (the model's range is 7% to 12%), from geology and well depth rather than local tests.

What individual samples found

Each row summarizes every public sample for that contaminant inside Indiana. 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
Arsenic 1958 to 2025	15%	1,498	73%	1.9	230	10 ug/L EPA limit
Nitrate 1930 to 2026	8%	6,062	70%	0.04	150	10 mg/L EPA limit
PFOS 2019 to 2021	6%	32	9%	0	26	4 ng/L EPA limit
PFOA 2019 to 2021	3%	32	13%	0	5.2	4 ng/L EPA limit
E. coli 2013 to 2019	3%	35	3%	0	1	0 MPN/100mL EPA limit
Fluoride 1949 to 2026	<1%	3,302	83%	0.2	355	4 mg/L EPA limit
Lead 1973 to 2025	<1%	1,226	46%	0	500	15 ug/L EPA limit
Radium (226 + 228) 1983 to 2020	<1%	125	71%	0.17	12	5 pCi/L EPA limit
Copper 1954 to 2025	0%	1,013	47%	0	0.24	1.3 mg/L EPA limit
Uranium 1980 to 2025	0%	329	70%	0.334	21.1	30 ug/L EPA limit
Chloride 1901 to 2026	no limit	6,616	99%	12	8,510	250 mg/L nuisance level
Iron 1901 to 2026	no limit	5,442	92%	500	1,500,000	300 ug/L nuisance level
Sodium 1930 to 2026	no limit	3,603	100%	18	5,600	20 mg/L health guideline
Manganese 1950 to 2026	no limit	3,433	89%	83	45,000	300 ug/L health guideline
Radon 1991 to 2019	no limit	161	99%	290	1,600	2,000 pCi/L health guideline

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	8%4,912 samples	11%402 samples	10%241 samples	9%507 samples
Fluoride	<1%2,881 samples	0%165 samples	0%111 samples	0%145 samples
Arsenic	14%1,203 samples	15%151 samples	13%76 samples	29%68 samples
Lead	1%952 samples	0%130 samples	0%76 samples	0%68 samples
Copper	0%739 samples	0%130 samples	0%76 samples	0%68 samples
Uranium	0%55 samples	0%130 samples	0%76 samples	0%68 samples

Arsenic above the limit in Indiana rose from 13% of 76 samples in the 2010s to 29% of 68 in the 2020s.

Nitrate, fluoride, lead, copper, uranium 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 arsenic (15% of 1,498 samples), nitrate (8% of 6,062 samples), and pfos (6% of 32 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 Indiana

1
Arsenic
15% of 1,498 local samples were above the limit.
2
Nitrate
8% of 6,062 local samples were above the limit.
3
PFOS
6% of 32 local samples were above the limit.
4
PFOA
3% of 32 local samples were above the limit.
5
E. coli
3% of 35 local samples were above the limit.
6
Fluoride
<1% of 3,302 local samples were above the limit.
7
Lead
<1% of 1,226 local samples were above the limit.
8
Volatile organic compounds (VOCs)
6,950 leaking underground storage tank sites on record locally.

Test your Indiana well for arsenic, nitrate and PFOS

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 Indiana: certified labs, state programs and prices.

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

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Send me the Indiana report

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

The rock under Indiana

Mississippian aquifers

Sandstone and carbonate-rock. Layered sandstone and limestone means a well may draw from either. Hardness and iron are routine, and the limestone layers can carry bacteria and nitrate from the surface quickly, so test for both yearly.

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 Indiana

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.

Well Water Quality and Testing, Indiana Department of Health
Laboratories, IDEM

Contamination sources on record in Indiana

IDEM records 6,950 leaking underground storage tank sites in Indiana, among 8,289 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.

6,950: leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
1,339: other remediation projects

Treatment that fits the local profile

Arsenic

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

Nitrate

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

PFOS

Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange

PFOA

Granular activated carbon whole-house; Point-of-use reverse osmosis; Anion exchange

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 arsenic

Under-sink reverse osmosis system

under-sink or countertop, about $300

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

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 arsenic

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 PFOS

Aquasana Claryum 3-Stage under-sink filter

under-sink or countertop, about $175

Certified to NSF/ANSI 53 to reduce 99% of lead and 99.7% of PFOA and PFOS at the tap. Not a fix for arsenic, nitrate or bacteria.

For PFOS

Whole-house PFAS carbon system

whole-house, at the point of entry, about $3,000

Granular activated carbon certified to NSF/ANSI 53 for PFOA and PFOS; replace media on schedule.

For PFOS

Aquasana HealthShield whole-house filter

whole-house, at the point of entry, about $2,099

Whole-house carbon system the maker certifies to reduce PFAS (PFOA and PFOS) and VOCs at every tap; a UV option adds bacteria protection.

Common questions

Is there arsenic in well water in Indiana?

Arsenic was detected in 73% of 1,498 public well samples in Indiana, and 15% 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 Indiana?

The median radon level across 161 public samples in Indiana was 290 pCi/L, with a high of 1,600 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.

How often should I test a private well in Indiana?

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 Indiana

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

Sources

USGS Water Quality Portal: 32,909 samples in Indiana. 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 1,677,339 people on private wells in Indiana 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.
IDEM regulated sites: 8,289 regulated sites located in Indiana. Leaking underground storage tank sites and state cleanup sites from the Indiana Department of Environmental Management. Retrieved September 16, 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.