Manganese and arsenic are worth checking in Story County wells.
2 worth checking, 3 rare out of 5 health checks.
From 29 wells tested in Story County since 2000; your own well needs its own test. How to read this
Not charted, because fewer than 10 wells were tested: uranium (2), radon (2).
Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+
Lab results: Water Quality Portal (USGS and EPA)
Who drinks from a well here
1 in 8 people 12,472 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 Story County compares with Iowa and the counties around it.
Each result puts Story County next to the 6 counties that border it, on the chart's 0 to 50% scale.
These 2 are worth checking in Story County.
Manganese4 of 27 wells over
Arsenic3 of 27 wells over
These 3 are rare in Story County.
Nitrate0 of 14 wells over
* Likely overstated, so we don't rank it.
Too few tested to show: Boone.
Fluoride0 of 27 wells over
Lead0 of 27 wells over
Too few Story County wells were tested for these 2.
Uranium2 wells tested
Radon in water2 wells tested
None of the 3 Story County wells tested for bacteria had it, but every well needs a yearly test.
Coliform bacteria0 of 3 wells had it
E. coli0 of 3 wells had it
E. coli means human or animal waste is getting in, so if a test of your Story County well finds it, boil drinking water until the well is fixed.
Iron reached staining levels in 21 of 27 tested wells, and it isn't a health risk.
Iron stains21 of 27 wells had it
Most of the 29 wells tested in Story County were last tested before 2010.
An old result shows the water as it was then, so treat these 29 wells as a starting point and test your own.
Most Story 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 4 things to check in Story County.
- Bacteria
- Nitrate
- Manganese
- Arsenic
What Iowa offers well owners
- Free testingIowa's Private Well Grants program provides free testing for bacteria, nitrate, arsenic, and manganese through participating county environmental health offices. See the program
- Certified labsIowa's list of certified labs
- Well recordsIowa's well record search
Half the household wells here are shallower than 200 feet.
That comes from 527 household wells in Iowa's drilling records. Most wells of every kind here are 81 to 210 feet deep. Wells as deep as Story 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 61 of the 92 other Iowa counties with enough drilling records.
Look up your own well's depth in Iowa'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 Story County.
Story 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 7 town water systems in Story County test for PFAS. 1 found some PFAS, all below the new limits. No well in Story County has 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 Story County
Is well water in Story County safe to drink?
4 of 27 wells tested in Story County had manganese over the limit, about 1 in 7. Across Iowa it's about 2 in 10. That's a smaller share than in 36 of the 67 other Iowa counties with 10 or more tested wells. So test your own well for manganese before you count on it.
Can I get my well tested for free in Story County?
Iowa's Private Well Grants program provides free testing for bacteria, nitrate, arsenic, and manganese through participating county environmental health offices. If not, use a lab Iowa has certified for drinking water. Ask for bacteria, nitrate, manganese and arsenic, the tests that matter most in Story County.
How deep are wells in Story County?
Half the household wells here are shallower than 200 feet. Typical household wells here go deeper than in 61 of the 92 other Iowa counties with enough drilling records.
How does Story County compare with the counties around it?
For manganese, the share of tested wells over the limit: 5 of the 6 neighboring counties with data had a higher share than Story County, at 15%. Hamilton had the most, at 43%. Groundwater doesn't stop at county lines, so Hamilton's 43% is worth knowing about if you live near it.
How often should I test my well in Story County?
None of the 3 wells tested for bacteria in Story 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 Story County numbers come from
- People on wells: 12,472 in Story County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 197 well water samples from 29 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2016.
- Well depths: 527 Iowa drilling records for Story County, gathered in the US Groundwater Well Database (Lin and others, 2024).
- Neighboring counties: the 6 counties that share a border with Story County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 7 town water systems in Story County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Story County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Iowa Department of Natural Resources, checked November 1, 2026.