Well water in Iosco County, Michigan
In Iosco County, 2% of 132 tested well samples exceeded the EPA limit for nitrate (10 mg/L), based on public data from USGS Water Quality Portal.
The strongest signal is arsenic: 14% of 14 local samples were above the limit, too few samples to carry the headline but first on the test list below.
330 test results across 10 contaminants from at least 62 wells, 1978 to 1996; nitrate has the most at 132. Data refreshed September 15, 2026.
Compiled by Nick at Well Water Nerd from public records. How these pages are built
An estimated 10,765 people in Iosco County get their drinking water from a private well, per USGS 2015 county water use. That is about 42% of residents.
Separately, the USGS national arsenic model estimates that 5% of the 10,765 people on private wells in Iosco 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 individual samples found
Each row summarizes every public sample for that contaminant inside Iosco 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 |
|---|---|---|---|---|---|---|
| Arsenic 1978 to 1988 | 14 | 57% | 0.5 | 20 | 10 ug/L EPA limit | |
| Nitrate 1978 to 1996 | 132 | 70% | 0.08 | 28 | 10 mg/L EPA limit | |
| Copper 1978 to 1986 | 36 | 97% | 0 | 0.039 | 1.3 mg/L EPA limit | |
| Lead 1978 to 1986 | 35 | 100% | 0 | 9 | 15 ug/L EPA limit | |
| Fluoride 1978 to 1988 | 14 | 93% | 0.5 | 1.4 | 4 mg/L EPA limit | |
| Chloride 1978 to 1988 | no limit | 51 | 100% | 4.3 | 2,500 | 250 mg/L nuisance level |
| Iron 1978 to 1988 | no limit | 14 | 100% | 320 | 1,000 | 300 ug/L nuisance level |
| Manganese 1978 to 1988 | no limit | 14 | 100% | 19.5 | 150 | 300 ug/L health guideline |
| Sodium 1978 to 1988 | no limit | 14 | 100% | 102 | 1,200 | 20 mg/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
The contaminants most often above their limit here are arsenic (14% of 14 samples) and nitrate (2% of 132 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 Iosco County
- 1Arsenic14% of 14 local samples were above the limit.
- 2Nitrate2% of 132 local samples were above the limit.
- 3Coliform bacteriaRecommended for every private well, every year.
- 4ChlorideDetected in 100% of local samples.
- 5IronDetected in 100% of local samples.
- 6ManganeseDetected in 100% of local samples.
- 7CopperDetected in 97% of local samples.
- 8Volatile organic compounds (VOCs)38 leaking underground storage tank sites on record locally.
- 9Metals panel66 hazardous waste sites on record locally.
Test your Iosco County well for arsenic, nitrate 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 Michigan: certified labs, state programs and prices.
Already have results back? Get your lab report read against the Iosco County numbers, $29. Every line explained, ranked by what matters, with the fix for each.
Wells in Iosco County
6,850 domestic wells in Iosco County are on record with the state since 1901. 26% are drilled into bedrock, and the typical well is 71 feet deep (one in ten goes past 257 feet).
In a typical Iosco County well, bedrock starts about 92 feet down, the median yield is 20 gallons per minute, <1% of wells yield under 3 gallons per minute and usually need a storage tank.
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 Iosco County
Marshall aquifer
Sandstone. Sandstone wells draw from pore space in the rock and tend to be dependable. Iron, manganese and hardness are common, and some sandstones carry arsenic or radium, so a first test should include both.
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 Iosco County
Michigan EGLE records 38 leaking underground storage tank sites and 66 hazardous waste sites in Iosco County, among 231 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.
- 38
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 66
- hazardous waste sitesSolvents, degreasers and metals from industrial sites can travel far in fractured bedrock.
- 127
- registered underground storage tank sitesRegistered tanks are regulated and inspected; they matter most when they are old or near a shallow well.
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
Chloride
Point-of-use reverse osmosis; Distillation
Iron
Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Manganese
Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
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 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 Iosco County
No water treatment company serves Iosco 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 Iosco County, and you get an email naming it first.
Common questions
How deep are wells in Iosco County?
The typical domestic well in Iosco County is 71 feet deep, based on 6,850 wells reported to the state since 1901. One in ten is deeper than 257 feet. 26% are drilled into bedrock.
Is there arsenic in well water in Iosco County?
Arsenic was detected in 57% of 14 public well samples in Iosco County, and 14% 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 Iosco 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 Iosco County
13 towns have fewer than 30 public samples and are included in the Iosco County totals above rather than shown separately: Alabaster township, Au Sable charter township, Baldwin township, Burleigh township, East Tawas, Grant township, Plainfield township, Reno township, Sherman township, Tawas City, Tawas township, Whittemore, Wilber township.
Counties near Iosco 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: 330 samples in Iosco 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 10,765 people on private wells in Iosco 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: 6,850 well records in Iosco County, 6,850 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: 231 regulated sites located in Iosco 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.