Well water in Mille Lacs County, Minnesota
In Mille Lacs County, 2% of 970 private wells tested between 2008 and 2021 had arsenic above the EPA limit (10 ug/L), according to the Minnesota Department of Health.
The strongest signal is nitrate: 4% of 114 local samples were above the limit, too few samples to carry the headline but first on the test list below.
970 private wells tested 2008 to 2021 in state summaries; 543 test results across 11 contaminants from at least 54 wells, 1965 to 2025; nitrate has the most at 114. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 16,858 people in Mille Lacs County get their drinking water from a private well, per USGS 2015 county water use. That is about 65% of residents.
Separately, the USGS national arsenic model estimates that 8% of the 16,858 people on private wells in Mille Lacs County draw water above 10 ug/L (the model's range is 6% to 10%), from geology and well depth rather than local tests.
What homeowner tests found
MDH new private well arsenic tests: private wells tested and reported to the state, 2008 to 2021. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.
| Contaminant | Above state level | Wells tested | Median | 95th pct | Highest | State level |
|---|---|---|---|---|---|---|
| Arsenic | 970 | 2 | 6.9 | 10 ug/L |
What individual samples found
Each row summarizes every public sample for that contaminant inside Mille Lacs 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 |
|---|---|---|---|---|---|---|
| Nitrate 1965 to 2006 | 114 | 50% | 0 | 39.4 | 10 mg/L EPA limit | |
| Fluoride 1965 to 2025 | 48 | 79% | 0.2 | 0.9 | 4 mg/L EPA limit | |
| Copper 1993 to 2025 | 26 | 12% | 0 | 0.165 | 1.3 mg/L EPA limit | |
| Lead 1993 to 2025 | 26 | 15% | 0 | 1.06 | 15 ug/L EPA limit | |
| Arsenic 1995 to 2025 | 25 | 20% | 0 | 4.08 | 10 ug/L EPA limit | |
| Chloride 1965 to 2025 | no limit | 113 | 100% | 18.7 | 338 | 250 mg/L nuisance level |
| Iron 1965 to 2025 | no limit | 61 | 85% | 269 | 7,150 | 300 ug/L nuisance level |
| Manganese 1965 to 2025 | no limit | 59 | 86% | 110 | 1,600 | 300 ug/L health guideline |
| Sodium 1968 to 2025 | no limit | 57 | 100% | 11 | 74 | 20 mg/L health guideline |
Sampled fewer than 10 times, too few to summarize: PFOS (5), PFOA (9).
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 addressWhat this means
Among homeowners in Mille Lacs County who sent a sample to the state lab, the health-based limits most often exceeded were arsenic (2% of 970 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.
What to test for in Mille Lacs County
- 1Nitrate4% of 114 local samples were above the limit.
- 2Arsenic2% of 970 local wells tested were above the EPA limit.
- 3Coliform bacteriaRecommended for every private well, every year.
- 4PFOSAbove the limit in 2 of 5 local samples; too few to quote a rate.
- 5PFOAAbove the limit in 3 of 9 local samples; too few to quote a rate.
- 6ChlorideDetected in 100% of local samples.
- 7ManganeseDetected in 86% of local samples.
- 8IronDetected in 85% of local samples.
- 9Volatile organic compounds (VOCs)115 leaking underground storage tank sites on record locally.
- 10Metals panel3 hazardous waste sites on record locally.
Test your Mille Lacs County well for nitrate, arsenic and coliform bacteria
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 $209Already 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 Minnesota: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Mille Lacs County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in Mille Lacs County
2,441 domestic wells in Mille Lacs County are on record with the state since 1952. 15% are drilled into bedrock, and the typical well is 72 feet deep (one in ten goes past 133 feet).
In a typical Mille Lacs County well, bedrock starts about 62 feet down.
Find your own well's report
The state keeps the driller's report for most wells drilled since 1984. It tells you how deep your well is, where bedrock starts, and how much water it makes, which decides what treatment can work.
- Open Minnesota Well Index and choose Water Well.
- The record shows depth, casing, depth to bedrock, aquifer, static water level and the driller; new wells since 2008 also show the arsenic test result.
Wells drilled since 1974 have records; older wells appear only if a later owner reported them.
The rock under Mille Lacs County
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 county centroid. A single well can sit in a different unit, especially near a boundary.
Official help in Minnesota
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 and Borings, Minnesota Department of Health
- Accredited Laboratories as Well Partners, Minnesota Department of Health
Contamination sources on record in Mille Lacs County
MPCA records 115 leaking underground storage tank sites and 3 hazardous waste sites in Mille Lacs County, among 274 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.
- 115
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 3
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 113
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 22
- lined landfills and transfer facilities
- 21
- other remediation projects
Treatment that fits the local profile
Nitrate
Point-of-use reverse osmosis; Anion exchange; Distillation
Manganese
Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
Iron
Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
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 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.
Free, no obligation
Get on the list for a free in-home water test in Mille Lacs County
No water treatment company serves Mille Lacs 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 Mille Lacs County, and you get an email naming it first.
Common questions
How deep are wells in Mille Lacs County?
The typical domestic well in Mille Lacs County is 72 feet deep, based on 2,441 wells reported to the state since 1952. One in ten is deeper than 133 feet. 15% are drilled into bedrock.
Is there arsenic in well water in Mille Lacs County?
Arsenic was detected in 20% of 25 public well samples in Mille Lacs County, and 0% 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 Mille Lacs 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 Mille Lacs County
24 towns have fewer than 30 public samples and are included in the Mille Lacs County totals above rather than shown separately: Bock, Bogus Brook township, Bradbury township, Dailey township, East Side township, Foreston, Greenbush township, Hayland township, Isle, Isle Harbor township, Kathio township, Lewis township, Milaca, Milaca township, Milo township, Mudgett township, Onamia, Onamia township, Page township, Pease, Princeton, Princeton township, South Harbor township, Wahkon.
Counties near Mille Lacs 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 Minnesota dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 543 samples in Mille Lacs 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.
- MDH new private well arsenic tests: summaries for 1 contaminants in Mille Lacs County, up to 970 wells each. Arsenic results for every new private well drilled and tested August 2008 to December 2021, reported to the Minnesota Department of Health by well contractors and published by county. Mandatory test on new wells only, so older wells are not represented; 64,793 wells statewide. Shares are against 10 ug/L, which MDH applies as its advice level. Median and 95th percentile published per county. Retrieved September 15, 2026.
- USGS national arsenic model (Ayotte 2017): estimated share of 16,858 people on private wells in Mille Lacs 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.
- Minnesota Well Index: 2,848 well records in Mille Lacs County, 2,441 domestic. Well construction records from the Minnesota Well Index (Minnesota Department of Health), non-public-supply wells. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 15, 2026.
- MPCA regulated sites: 274 regulated sites located in Mille Lacs County. Tank, leak, remediation, Superfund and landfill sites from the Minnesota Pollution Control Agency What's In My Neighborhood database. Retrieved September 15, 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.