Arsenic, lead and nitrate are worth checking in Kootenai County wells.
3 worth checking, 2 rare out of 5 health checks.
From 53 wells tested in Kootenai 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 8 people 21,229 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 Kootenai County compares with Idaho and the counties around it.
Each result puts Kootenai County next to the 4 counties that border it, on the chart's 0 to 50% scale.
These 3 are worth checking in Kootenai County.
Arsenic5 of 52 wells over
Lead2 of 28 wells over
Nitrate3 of 52 wells over
These 2 are rare in Kootenai County.
Manganese2 of 44 wells over
Fluoride0 of 45 wells over
* Likely overstated, so we don't rank it.
Every well needs a bacteria test every year.
No bacteria tests from Kootenai County wells are in the public data. Test every year anyway.
Iron reached staining levels in 8 of 44 tested wells, and it isn't a health risk.
Iron stains8 of 44 wells had it
Most of the 53 wells tested in Kootenai County were last tested before 2010.
An old result shows the water as it was then, so treat these 53 wells as a starting point and test your own.
Most Kootenai 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 Kootenai County.
- Bacteria
- Nitrate
- Arsenic
- Lead
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 Kootenai County.
Kootenai 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 8 town water systems in Kootenai County test for PFAS. 2 found some PFAS, all below the new limits. No well in Kootenai 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 Kootenai County
Is well water in Kootenai County safe to drink?
5 of 52 wells tested in Kootenai 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 29 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 Kootenai 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 lead, the tests that matter most in Kootenai County.
How does Kootenai 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 Kootenai County, at 10%. 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 Kootenai County?
Kootenai 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 Kootenai County numbers come from
- People on wells: 21,229 in Kootenai County, from EPA estimates built on the 2020 Census (Murray et al.).
- Lab tests: 1,095 well water samples from 53 wells in the Water Quality Portal, run by the USGS and EPA, 2000 to 2015.
- Neighboring counties: the 4 counties that share a border with Kootenai County, from the Census Bureau's county adjacency file.
- PFAS: EPA tests of 8 town water systems in Kootenai County under the Fifth Unregulated Contaminant Monitoring Rule, 2023 to 2025.
- Radon: Kootenai County is zone 1 on the EPA Map of Radon Zones.
- State programs and links: Department of Health and Welfare, checked November 1, 2026.