Radon levels in Coeur d'Alene, Idaho
ModerateEPA Zone 1Predicted long-term basement average of 2.6 pCi/L (model estimate) across the 2 modeled ZIP codes in Coeur d'Alene - about 1.5× the US average of 1.8, close to the Idaho average of 2.6. Ranked #2 of 9 Idaho cities on this site. Most of the city lies in Kootenai County.
Test Coeur d'Alene, ID - the EPA says "consider fixing" in this range
The predicted basement average here is 2.6 pCi/L, in the 2-4 pCi/L band where the EPA recommends considering mitigation. Plenty of individual homes in a moderate area test above 4. Start with a short-term test; if it comes back at 2 or higher, follow up with a long-term test or a continuous monitor.
Already tested at 4 pCi/L or higher? Find a certified mitigation professional (EPA). A mitigation system typically runs $800-$2,500 installed.
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Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. Measured state test results are shown separately below, labeled with their source and years. How the numbers work.
2.6 ± 0.11
pCi/L predicted basement mean (model SD)
1.8 ± 0.13
pCi/L predicted upstairs (above-ground) mean
2.4-2.9
range of ZIP-level basement predictions in the city
0%
of Coeur d'Alene ZIPs predicted ≥ 4 pCi/L (100% ≥ 2)
Measured radon tests in Kootenai County (Idaho Department of Health and Welfare, through 2019)
Actual results from home radon tests reported to the state, separate from the model estimate above. Coverage: through 2019 (start year not stated by the source).
- Measured mean
- 13.3 pCi/L
- Results ≥ 4 pCi/L
- 54.8%
- Sample
- 8,886 tests
| Figure | Model (predicted) | State tests (measured) |
|---|---|---|
| Mean, pCi/L | 3.7 basement | 13.3 |
| Share ≥ 4 pCi/L | not a model output | 54.8% |
The measured mean runs 9.6 pCi/L above the model because state test data is voluntary and skews toward basements, winter, and homeowners who already suspected a problem, while the model estimates the long-term average across all homes.
Source: Home Radon Test Results by Zip Code, Idaho Department of Health and Welfare, Indoor Environment / Radon Program. No license statement on the public feature service (publicly shared by the IDHW environmental-health account). Method and download.
What this means for Coeur d'Alene
The typical Coeur d'Alene home is predicted in the 2-4 pCi/L band. The EPA's guidance for this range is to consider fixing, because there is no known safe level and a meaningful minority of homes in a moderate area will test above 4.
The city figure is not a separate estimate: it is the mean of the model's ZIP-code predictions, weighted by the share of the city's land in each ZIP (Census 2020 ZCTA-to-place relationship file). Note that the EPA classifies Kootenai County as Zone 1 while the newer model predicts 2.6 pCi/L for Coeur d'Alene; where they disagree, we grade on the model but show both.
Comparable Idaho cities: Idaho Falls (2.6), Pocatello (2.5), Boise (2.4), Twin Falls (2.4).
ZIP codes in Coeur d'Alene
ZIPs that overlap the city, largest share of its land first. Predicted basement and upstairs means are model estimates; ZIPs the model does not cover show a dash.
| ZIP | Share of city | Basement | Upstairs | Grade |
|---|---|---|---|---|
| 83815 | 59% | 2.4 ± 0.13 | 1.5 | Moderate |
| 83814 | 42% | 2.9 ± 0.09 | 2.2 | Moderate |
Testing help in Idaho
Idaho's radon program page is at healthandwelfare.idaho.gov and, when we checked it, offered a free test kit (one per address every two years; listed as out of stock when checked). EPA state radon contacts page. If a test comes back at 4 pCi/L or higher, mitigation typically costs $800-$2,500 installed; use EPA find-a-professional and read the mitigation guide.
Coeur d'Alene radon questions
- Is radon high in Coeur d'Alene, Idaho?
- Moderate. Averaging the model's ZIP-code predictions across Coeur d'Alene (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 2.6 pCi/L - about 1.5× the US average of 1.8 and close to the Idaho average of 2.6. That is in the 2-4 pCi/L range where the EPA says to consider fixing. Coeur d'Alene ranks 2 of 9 Idaho cities on this site.
- What do actual radon tests show around Coeur d'Alene?
- Idaho Department of Health and Welfare publishes results for Kootenai County (not the city alone) covering through 2019 (8,886 tests): an average of 13.3 pCi/L, 54.8% of results at or above the 4 pCi/L action level. These are voluntary home tests, so they skew toward basements and toward homes where radon was suspected; the model's predicted basement average for Coeur d'Alene is 2.6 pCi/L.
- Which Coeur d'Alene ZIP codes have the highest radon?
- Predictions for the 2 modeled ZIP codes in Coeur d'Alene range from 2.4 to 2.9 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 100% at or above 2. The city is fairly uniform, so the city-wide number is a reasonable guide for any neighborhood.
- Should I test for radon in Coeur d'Alene?
- Yes, soon. With a predicted basement average of 2.6 pCi/L, a meaningful share of Coeur d'Alene homes will test above the 4 pCi/L action level. Start with a short-term kit; if it reads 2 or higher, confirm with a long-term test or a continuous monitor before paying for mitigation.
- What does EPA Radon Zone 1 mean for Coeur d'Alene?
- Coeur d'Alene sits mainly in Kootenai County, which the EPA classifies as Zone 1 - highest potential (predicted average > 4 pCi/L). The zone map dates from 1993 and covers whole counties. The newer model's city average of 2.6 pCi/L does not line up with Zone 1, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.
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