Manganese is widespread in Hennepin County wells.
1 widespread, 2 worth checking, 3 rare out of 6 health checks.
From 163 wells tested in Hennepin County since 2000; your own well needs its own test. How to read this
Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+
Lab results: Water Quality Portal (USGS and EPA)
Who drinks from a well here
About 1 in 21 people 62,239 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
How deep wells go here
Deep wells: fewer surface germs, more minerals from the rock.
Well depths: US Groundwater Well Database
Radon risk (a gas from rock)
Likely here. Test your home's air first.
Radon zones: EPA map
Here's how Hennepin County compares with Minnesota and the counties around it.
Each result puts Hennepin County next to the 7 counties that border it, on the chart's 0 to 50% scale.
This one is widespread in Hennepin County wells.
Manganese97 of 159 wells over
Too few tested to show: Carver, Scott, Wright.
These 2 are worth checking in Hennepin County.
Arsenic15 of 140 wells over
Too few tested to show: Scott.
Uranium2 of 23 wells over
Too few tested to show: Anoka, Carver, Ramsey, Scott, Wright.
These 3 are rare in Hennepin County.
Nitrate6 of 155 wells over
Too few tested to show: Ramsey.
Lead0 of 140 wells over
Too few tested to show: Scott.
None of the 9 Hennepin County wells tested for bacteria had it, but every well needs a yearly test.
Coliform bacteria0 of 9 wells had it
E. coli0 of 9 wells had it
E. coli means human or animal waste is getting in, so if a test of your Hennepin County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 96 of 158 tested wells, and it isn't a health risk.
Iron stains96 of 158 wells had it
Too few tested to show: Scott.
Hennepin County has 163 tested wells, and the busiest decade for testing was the 2010s.
Only 34 of the 163 wells have a test from 2020 or later, so a fresh test of your own well tells you more than any of these.
Most Hennepin County wells in these records were tested for research or because someone suspected a problem, which can push the shares above what a typical home well would show (how we read the numbers).
One mail-in lab test covers the 5 things to check in Hennepin County.
- Bacteria
- Nitrate
- Manganese
- Arsenic
- Uranium
What Minnesota offers well owners
- Free testingWe didn't find a free program for all of Minnesota. Minnesota's private well page
- Certified labsMinnesota's list of certified labs
- Well recordsMinnesota's well record search
- New wellsThe well contractor must collect an initial water sample after construction to test for coliform bacteria, nitrate, and arsenic before the well is used.
Half the household wells here are shallower than 155 feet.
That comes from 17,590 household wells in Minnesota's drilling records. Most wells of every kind here are 95 to 205 feet deep. Wells as deep as Hennepin County's are usually better protected from fertilizer and bacteria at the surface, but they can pick up more of what's in the rock, like arsenic and uranium. Typical household wells here go deeper than in 58 of the 86 other Minnesota counties with enough drilling records.
Look up your own well's depth in Minnesota's well record search, or see how to find it.
Well depths: US Groundwater Well Database
Here's what we know about radon and PFAS in Hennepin County.
Hennepin County is in the EPA's highest radon zone. Radon from well water adds to the radon in your indoor air, so test your air first, and your water too if the air is high. Radon guide
Between 2023 and 2025 the EPA had 25 town water systems in Hennepin County test for PFAS. 2 of them had at least one test above 4 ng/L, the new EPA limit for PFOA and PFOS. The highest single result was 10 ng/L of PFOA. Only 26 wells in Hennepin County have public PFAS results, so the town systems are the best clue to what's in the groundwater nearby. PFAS guide
Radon zones: EPA Map of Radon Zones. PFAS: EPA tests of town water systems, 2023 to 2025
Questions people ask about well water in Hennepin County
Is well water in Hennepin County safe to drink?
97 of 159 wells tested in Hennepin County had manganese over the limit, about 6 in 10. Across Minnesota it's about 2 in 10. That's a bigger share than in 43 of the 44 other Minnesota counties with 10 or more tested wells, leaving out 1 county whose results are likely overstated. So test your own well for manganese before you count on it.
Where can I get my well tested in Hennepin County?
Use a lab Minnesota has certified for drinking water. Minnesota's list is linked above, in the box about testing. Ask for bacteria, nitrate, manganese, arsenic and uranium, the tests that matter most in Hennepin County.
How deep are wells in Hennepin County?
Half the household wells here are shallower than 155 feet. Typical household wells here go deeper than in 58 of the 86 other Minnesota counties with enough drilling records.
How does Hennepin County compare with the counties around it?
For manganese, the share of tested wells over the limit: Hennepin County, at 61%, had a higher share than all 4 neighboring counties with data. Groundwater doesn't stop at county lines, so Anoka's 43% is worth knowing about if you live near it.
How often should I test my well in Hennepin County?
None of the 9 wells tested for bacteria in Hennepin County had it, but the CDC still says to test for bacteria and nitrate every year, and right away after a flood, a repair, or any change in taste or smell.
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Where the Hennepin County numbers come from
- People on wells: 62,239 in Hennepin County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 2,568 well water samples from 163 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2025.
- Well depths: 17,590 Minnesota drilling records for Hennepin County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 7 counties that share a border with Hennepin County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 25 town water systems in Hennepin County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Hennepin County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Minnesota Department of Health, checked November 1, 2026.