Well water in Brown County, Wisconsin

In Brown County, 3% of 532 private wells tested between 1993 and 2025 had arsenic above the Wisconsin enforcement standard (10 ug/L), according to the UWSP Well Water Quality Viewer.

1,748 private wells tested 2002 to 2025 in state summaries; 1,443 test results across 12 contaminants from at least 117 wells, 1891 to 2015; nitrate has the most at 330. Data refreshed September 15, 2026.

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

An estimated 28,296 people in Brown County get their drinking water from a private well, per USGS 2015 county water use. That is about 11% of residents.

Separately, the USGS national arsenic model estimates that 5% of the 28,296 people on private wells in Brown County draw water above 10 ug/L (the model's range is 4% to 6%), from geology and well depth rather than local tests.

What homeowner tests found

Wisconsin Well Water Quality Viewer samples: private wells tested and reported to the state, 2002 to 2025. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA. County and state figures combine the town summaries, weighted by wells tested; medians are not combined.

Contaminant	Above state level	Wells tested	Highest	State level
Sodium	10%	70	167	20 mg/L
Iron	9%	70	11,460	300 ug/L
Arsenic	3%	532	615	10 ug/L
Nitrate	3%	1,748	26.5	10 mg/L
Lead	3%	76	55	15 ug/L
Total coliform	2%	126
Chloride	2%	126	317	250 mg/L
Manganese	1%	76	317	300 ug/L
Copper	0%	76	1.05	1.3 mg/L
E. coli	0%	2

What individual samples found

Each row summarizes every public sample for that contaminant inside Brown County. 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 1976 to 2015	2%	65	66%	0	21	15 ug/L EPA limit
Arsenic 1976 to 2015	2%	65	86%	1	14	10 ug/L EPA limit
Nitrate 1947 to 2015	<1%	330	54%	0.01	12	10 mg/L EPA limit
Fluoride 1946 to 2015	0%	142	99%	1.6	3.8	4 mg/L EPA limit
Copper 1976 to 2015	0%	38	71%	0.002	0.077	1.3 mg/L EPA limit
Chloride 1891 to 2015	no limit	263	100%	16	680	250 mg/L nuisance level
Sodium 1891 to 2015	no limit	203	100%	24	500	20 mg/L health guideline
Iron 1946 to 2015	no limit	158	96%	365	4,900	300 ug/L nuisance level
Manganese 1946 to 2015	no limit	157	98%	11	3,000	300 ug/L health guideline

Sampled fewer than 10 times, too few to summarize: Radium (226 + 228) (8), Uranium (8), Radon (6).

Closer than the county

See the sampled wells near your address

The same records, drawn around one point: which wells within a few miles were sampled and what they found, how deep the wells next to you were drilled, and any leaking tank or cleanup site within a mile.

Check my address

What this means

Among homeowners in Brown County who sent a sample to the state lab, the health-based limits most often exceeded were arsenic (3% of 532 wells), nitrate (3% of 1,748 wells), and lead (3% of 76 wells). These are ordinary wells tested by their owners, so the shares are the best available picture of a typical well here, with one caveat: people test more often when they suspect a problem.

Sodium exceeds the state's advisory level in a sizable share of wells; this is mostly a taste, staining or diet issue rather than a toxicity one.

What to test for in Brown County

1
Arsenic
3% of 532 local wells tested were above the Wisconsin enforcement standard.
2
Nitrate
3% of 1,748 local wells tested were above the Wisconsin enforcement standard.
3
Lead
3% of 76 local wells tested were above the Wisconsin enforcement standard.
4
Total coliform
2% of 126 local wells tested were above the Wisconsin limit (any detection).
5
Coliform bacteria
Recommended for every private well, every year.
6
Radon
Median local reading is 325 pCi/L.
7
Sodium
10% of 70 local wells tested were above the EPA advisory level.
8
Iron
9% of 70 local wells tested were above the Wisconsin nuisance level.
9
Volatile organic compounds (VOCs)
429 leaking underground storage tank sites on record locally.

Test your Brown County well for arsenic, nitrate and lead

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 Wisconsin: certified labs, state programs and prices.

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

Official help in Wisconsin

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.

Wells, Wisconsin DNR
Laboratory Certification, Wisconsin DNR

Contamination sources on record in Brown County

Wisconsin DNR records 429 leaking underground storage tank sites in Brown County, among 1,168 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.

429: leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
58: lined landfills and transfer facilities
681: other remediation projects

Treatment that fits the local profile

Sodium

Point-of-use reverse osmosis; Distillation

Iron

Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration

Arsenic

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

Nitrate

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

Lead

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

Fluoride

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

Under-sink reverse osmosis system

under-sink or countertop, about $300

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

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.

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 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 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 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.

Free, no obligation

Get on the list for a free in-home water test in Brown County

No water treatment company serves Brown County through Well Water Nerd yet. We are signing licensed companies on county by county: they test at your tap for free, walk you through the numbers, and quote treatment only if something needs fixing. Leave your details and you are first in line. Nothing is shared until a company joins for Brown County, and you get an email naming it first.

Common questions

Is there arsenic in well water in Brown County?

Arsenic was detected in 86% of 65 public well samples in Brown County, 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 Brown County?

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.

Towns in Brown County

6 towns have fewer than 30 public samples and are included in the Brown County totals above rather than shown separately: Allouez village, Denmark village, De Pere, Howard village, Pulaski village, Wrightstown village.

Counties near Brown County

Closest first. Groundwater does not stop at a line on a map, so the next county over is a fair second opinion.

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

Sources

USGS Water Quality Portal: 1,443 samples in Brown County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
Wisconsin Well Water Quality Viewer samples: summaries for 10 contaminants in Brown County, up to 1,748 wells each. Private well samples compiled by the UWSP Center for Watershed Science and Education from the DNR Groundwater Retrieval Network, DATCP surveys, the UWSP Water and Environmental Analysis Lab and county health programs, published in the Wisconsin Well Water Quality Viewer with Wisconsin DHS. Samples are located to the town, village or city they fall in; one result per well and parameter (the latest) so repeat samples do not double count; wells without a state well number are keyed by location. Shares are against Wisconsin NR 140 enforcement standards (arsenic 10 ug/L, nitrate 10 mg/L as N, manganese 300 ug/L, lead 15 ug/L, copper 1.3 mg/L) and the iron and chloride secondary levels. Many samples were submitted by homeowners with a reason to test, so shares can run above a random survey. Retrieved September 9, 2026.
USGS national arsenic model (Ayotte 2017): estimated share of 28,296 people on private wells in Brown County 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.
Wisconsin DNR regulated sites: 1,168 regulated sites located in Brown County. Open and closed remediation activities (BRRTS, including leaking underground storage tanks and spills) and landfill and waste sites from the Wisconsin Department of Natural Resources. 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.