Arsenic and manganese are worth checking in Bonner County wells.
2 worth checking, 3 rare out of 5 health checks.
From 57 wells tested in Bonner 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
1 in 2 people 23,298 people
Nobody else tests these wells. Only you do.
People on wells: EPA researchers' 2020 estimate
Radon risk (a gas from rock)
Likely here. Test your home's air first.
Radon zones: EPA map
Here's how Bonner County compares with Idaho and the counties around it.
Each result puts Bonner County next to the 7 counties that border it, on the chart's 0 to 50% scale.
These 2 are worth checking in Bonner County.
Arsenic6 of 57 wells over
Too few tested to show: Lincoln, MT, Pend Oreille, WA, Sanders, MT.
Manganese4 of 57 wells over
Too few tested to show: Lincoln, MT, Pend Oreille, WA, Sanders, MT.
These 3 are rare in Bonner County.
Lead0 of 14 wells over
Too few tested to show: Boundary, Lincoln, MT, Pend Oreille, WA, Sanders, MT.
Nitrate0 of 57 wells over
Too few tested to show: Lincoln, MT, Pend Oreille, WA, Sanders, MT.
Fluoride0 of 57 wells over
* Likely overstated, so we don't rank it.
Too few tested to show: Lincoln, MT, Pend Oreille, WA, Sanders, MT.
Every well needs a bacteria test every year.
No bacteria tests from Bonner County wells are in the public data. Test every year anyway.
Iron reached staining levels in 9 of 57 tested wells, and it isn't a health risk.
Iron stains9 of 57 wells had it
Too few tested to show: Lincoln, MT, Pend Oreille, WA, Sanders, MT.
Most of the 57 wells tested in Bonner County were last tested before 2010.
An old result shows the water as it was then, so treat these 57 wells as a starting point and test your own.
Most Bonner 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 Bonner County.
- Bacteria
- Nitrate
- Arsenic
- Manganese
What Idaho offers well owners
- Free testingDHW offers free private well water testing kits through Idaho Health Tools, limited to one kit per household every five years. See the program
- Certified labsIdaho's list of certified labs
- Well recordsIdaho's well record search
Here's what we know about radon and PFAS in Bonner County.
Bonner 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 2 town water systems in Bonner County test for PFAS. None found any. No well in Bonner 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 Bonner County
Is well water in Bonner County safe to drink?
6 of 57 wells tested in Bonner County had arsenic over the limit, about 1 in 10. Across Idaho it's about 1 in 10. That's a bigger share than in 30 of the 42 other Idaho counties with 10 or more tested wells, leaving out 1 county whose results are likely overstated. So test your own well for arsenic before you count on it.
Can I get my well tested for free in Bonner County?
DHW offers free private well water testing kits through Idaho Health Tools, limited to one kit per household every five years. If not, use a lab Idaho has certified for drinking water. Ask for bacteria, nitrate, arsenic and manganese, the tests that matter most in Bonner County.
How does Bonner County compare with the counties around it?
For arsenic, the share of tested wells over the limit: 2 of the 4 neighboring counties with data had a higher share than Bonner County, at 11%. Shoshone had the most, at 25%. Groundwater doesn't stop at county lines, so Shoshone's 25% is worth knowing about if you live near it.
How often should I test my well in Bonner County?
Bonner 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 Bonner County numbers come from
- People on wells: 23,298 in Bonner County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 744 well water samples from 57 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2011.
- Neighboring counties: the 7 counties that share a border with Bonner County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 2 town water systems in Bonner County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Bonner County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Department of Health and Welfare, checked November 1, 2026.