Well water in Monroe County, Michigan
In Monroe County, none of 117 tested well samples exceeded the EPA limit for nitrate, based on public data from USGS Water Quality Portal.
The strongest signal is coliform bacteria: Recommended for every private well, every year, too few samples to carry the headline but first on the test list below.
569 test results across 10 contaminants from at least 69 wells, 1961 to 1992; nitrate has the most at 117. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 27,777 people in Monroe County get their drinking water from a private well, per USGS 2015 county water use. That is about 19% of residents.
Separately, the USGS national arsenic model estimates that 19% of the 27,777 people on private wells in Monroe County draw water above 10 ug/L (the model's range is 15% to 28%), from geology and well depth rather than local tests.
What individual samples found
Each row summarizes every public sample for that contaminant inside Monroe 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 1961 to 1992 | 117 | 26% | 0 | 1.24 | 10 mg/L EPA limit | |
| Fluoride 1961 to 1992 | 56 | 100% | 1 | 2.7 | 4 mg/L EPA limit | |
| Lead 1971 to 1992 | 50 | 12% | 0 | 7 | 15 ug/L EPA limit | |
| Arsenic 1971 to 1992 | 50 | 12% | 0 | 7 | 10 ug/L EPA limit | |
| Copper 1979 to 1992 | 47 | 19% | 0 | 0.007 | 1.3 mg/L EPA limit | |
| Chloride 1961 to 1992 | no limit | 69 | 100% | 12 | 600 | 250 mg/L nuisance level |
| Sodium 1961 to 1992 | no limit | 58 | 100% | 22.5 | 250 | 20 mg/L health guideline |
| Iron 1961 to 1992 | no limit | 58 | 97% | 97 | 2,600 | 300 ug/L nuisance level |
| Manganese 1961 to 1992 | no limit | 58 | 95% | 8 | 170 | 300 ug/L health guideline |
Sampled fewer than 10 times, too few to summarize: Uranium (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 addressWhat this means
Among contaminants with a federal limit, no tested sample in Monroe County came back above it. That is reassuring, but sampling is uneven: wells that were never tested are not in this data.
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 Monroe County
- 1Coliform bacteriaRecommended for every private well, every year.
- 2NitrateRecommended for every private well, especially near farms or septic systems.
- 3FluorideDetected in 100% of local samples.
- 4ChlorideDetected in 100% of local samples.
- 5IronDetected in 97% of local samples.
- 6ManganeseDetected in 95% of local samples.
- 7Volatile organic compounds (VOCs)72 leaking underground storage tank sites on record locally.
- 8Metals panel189 hazardous waste sites on record locally.
Test your Monroe County well for coliform bacteria, nitrate and fluoride
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 Michigan: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Monroe County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in Monroe County
17,029 domestic wells in Monroe County are on record with the state since 1931. 98% are drilled into bedrock, and the typical well is 80 feet deep (one in ten goes past 122 feet).
In a typical Monroe County well, bedrock starts about 30 feet down, the median yield is 13 gallons per minute, <1% of wells yield under 3 gallons per minute and usually need a storage tank.
Bedrock wells are where arsenic, uranium and radon come from: the water sits in fractures in granite and metamorphic rock and picks up whatever the rock carries. That is why testing for those three matters more here than in a dug or gravel well.
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 Wellogic (EGLE) and choose Water Well.
- The record lists depth, casing, static water level, the pump test and the geologic log.
Michigan has required well records since 1966, so most drilled wells are on file.
The rock under Monroe County
Silurian-Devonian aquifers
Carbonate-rock. Limestone and dolomite move water through cracks and solution channels, sometimes very fast. Bacteria and nitrate can travel from the surface to a well in days, so annual bacteria testing matters more here than most places; hardness is a given.
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 Michigan
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.
- Private Residential Water Well Testing, Michigan EGLE
- Laboratory certification program, Michigan EGLE
Contamination sources on record in Monroe County
Michigan EGLE records 72 leaking underground storage tank sites and 189 hazardous waste sites in Monroe County, among 624 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.
- 72
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 189
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 361
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
- 2
- lined landfills and transfer facilities
Treatment that fits the local profile
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 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 Monroe County
No water treatment company serves Monroe 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 Monroe County, and you get an email naming it first.
Common questions
How deep are wells in Monroe County?
The typical domestic well in Monroe County is 80 feet deep, based on 17,029 wells reported to the state since 1931. One in ten is deeper than 122 feet. 98% are drilled into bedrock.
Is there arsenic in well water in Monroe County?
Arsenic was detected in 12% of 50 public well samples in Monroe 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 Monroe 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 Monroe County
20 towns have fewer than 30 public samples and are included in the Monroe County totals above rather than shown separately: Ash township, Bedford township, Berlin charter township, Dundee township, Erie township, Exeter township, Flat Rock, Frenchtown township, Ida township, La Salle township, London township, Luna Pier, Milan, Milan township, Monroe, Monroe charter township, Petersburg, Raisinville township, Summerfield township, Whiteford township.
Counties near Monroe 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 Michigan dataset as CSV, every county and town, with the sources named.
Sources
- USGS Water Quality Portal: 569 samples in Monroe 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.
- USGS national arsenic model (Ayotte 2017): estimated share of 27,777 people on private wells in Monroe 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.
- Michigan Wellogic well records: 17,029 well records in Monroe County, 17,029 domestic. Water well records from Wellogic, the Michigan Department of Environment, Great Lakes, and Energy statewide well database. Only aggregates are shown; owner names and addresses are never stored. Retrieved September 16, 2026.
- Michigan EGLE regulated sites: 624 regulated sites located in Monroe County. Part 201 environmental contamination sites, underground storage tank facilities and Part 115 landfills from the Michigan Department of Environment, Great Lakes, and Energy. 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.