Manganese, arsenic and fluoride are widespread in McLean County wells.
3 widespread, 3 rare out of 6 health checks.
From 15 wells tested in McLean County since 2004; 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
5 in 10 people 5,304 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
How deep wells go here
Middle depth: some shelter from the surface, not complete.
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 McLean County compares with North Dakota and the counties around it.
Each result puts McLean County next to the 8 counties that border it, on the chart's 0 to 50% scale.
These 3 are widespread in McLean County wells.
Manganese3 of 11 wells over
Too few tested to show: Burleigh, McHenry, Mercer, Oliver, Sheridan, Ward.
Arsenic3 of 11 wells over
Too few tested to show: Burleigh, McHenry, Mercer, Oliver, Sheridan, Ward.
Fluoride3 of 11 wells over
Too few tested to show: Burleigh, McHenry, Mercer, Oliver, Sheridan, Ward.
These 3 are rare in McLean County.
Uranium0 of 10 wells over
Too few tested to show: Burleigh, McHenry, Mercer, Oliver, Sheridan, Ward.
Nitrate0 of 14 wells over
Too few tested to show: Burleigh, McHenry, Mercer, Oliver, Sheridan, Ward.
Lead0 of 11 wells over
Too few tested to show: Burleigh, McHenry, Mercer, Oliver, Sheridan, Ward.
Every well needs a bacteria test every year.
No bacteria tests from McLean County wells are in the public data. Test every year anyway.
Iron reached staining levels in 7 of 11 tested wells, and it isn't a health risk.
Iron stains7 of 11 wells had it
Too few tested to show: Burleigh, McHenry, Mercer, Oliver, Sheridan, Ward.
McLean County has 15 tested wells, and the busiest decade for testing was the 2010s.
Only 3 of the 15 wells have a test from 2020 or later, so a fresh test of your own well tells you more than any of these.
Most McLean 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 McLean County.
- Bacteria
- Nitrate
- Arsenic
- Manganese
- Fluoride
What North Dakota offers well owners
- Free testingWe didn't find a free program for all of North Dakota. North Dakota's private well page
- Certified labsNorth Dakota's list of certified labs
- Well recordsNorth Dakota's well record search
Half the household wells here are shallower than 120 feet.
That comes from 71 household wells in North Dakota's drilling records. Most wells of every kind here are 55 to 160 feet deep. Wells as deep as McLean 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 are shallower than in 17 of the 24 other North Dakota counties with enough drilling records.
Look up your own well's depth in North Dakota'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 McLean County.
McLean 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
Radon zones: EPA Map of Radon Zones
Questions people ask about well water in McLean County
Is well water in McLean County safe to drink?
3 of 11 wells tested in McLean County had arsenic over the limit, about 3 in 10. Across North Dakota it's about 3 in 10. That's a bigger share than in 6 of the 8 other North Dakota counties with 10 or more tested wells. So test your own well for arsenic before you count on it.
Where can I get my well tested in McLean County?
Use a lab North Dakota has certified for drinking water. North Dakota's list is linked above, in the box about testing. Ask for bacteria, nitrate, arsenic, manganese and fluoride, the tests that matter most in McLean County.
How deep are wells in McLean County?
Half the household wells here are shallower than 120 feet. Typical household wells here are shallower than in 17 of the 24 other North Dakota counties with enough drilling records.
How does McLean County compare with the counties around it?
For manganese, the share of tested wells over the limit: 1 of the 2 neighboring counties with data had a higher share than McLean County, at 27%. Mountrail had the most, at 36%. Groundwater doesn't stop at county lines, so Mountrail's 36% is worth knowing about if you live near it.
How often should I test my well in McLean County?
McLean County has no public bacteria results for wells, so follow the CDC's advice: 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 McLean County numbers come from
- People on wells: 5,304 in McLean County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 126 well water samples from 15 wells in the Water Quality Portal, run by the USGS and EPA, 2004 to 2023.
- Well depths: 71 North Dakota drilling records for McLean County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 8 counties that share a border with McLean County, from the Census Bureau's county adjacency file.
- Radon: McLean County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Department of Environmental Quality, checked November 1, 2026.