Radon levels in Cincinnati, Ohio
LowEPA Zone 1Predicted long-term basement average of 1.6 pCi/L (model estimate) across the 27 modeled ZIP codes in Cincinnati - close to the US average of 1.8, about 45% below the Ohio average of 2.8. Ranked #22 of 27 Ohio cities on this site. Most of the city lies in Hamilton County.
Test Cincinnati, OH once anyway - radon varies house to house
The predicted basement average here is 1.6 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.
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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. How the numbers work.
1.6 ± 0.06
pCi/L predicted basement mean (model SD)
0.9 ± 0.07
pCi/L predicted upstairs (above-ground) mean
1.3-2.1
range of ZIP-level basement predictions in the city
0%
of Cincinnati ZIPs predicted ≥ 4 pCi/L (4% ≥ 2)
What this means for Cincinnati
The typical Cincinnati home is predicted below 2 pCi/L, the lowest band. That describes the average house; the ZIP-level predictions inside the city still span 1.3 to 2.1 pCi/L.
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 Hamilton County as Zone 1 while the newer model predicts 1.6 pCi/L for Cincinnati; where they disagree, we grade on the model but show both.
Comparable Ohio cities: Cleveland Heights (1.5), Lorain (1.7), Parma (1.8), Cleveland (1.3).
ZIP codes in Cincinnati
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 |
|---|---|---|---|---|
| 45226 | 7% | 1.6 ± 0.05 | 1.0 | Low |
| 45230 | 7% | 1.7 ± 0.06 | 1.1 | Low |
| 45211 | 6% | 1.9 ± 0.06 | 1.0 | Low |
| 45223 | 6% | 1.5 ± 0.06 | 0.9 | Low |
| 45208 | 6% | 1.7 ± 0.07 | 0.9 | Low |
| 45232 | 5% | 1.3 ± 0.06 | 0.7 | Low |
| 45224 | 5% | 1.8 ± 0.05 | 1.0 | Low |
| 45238 | 5% | 1.9 ± 0.06 | 1.0 | Low |
| 45237 | 4% | 1.4 ± 0.06 | 0.8 | Low |
| 45204 | 4% | 1.4 ± 0.06 | 0.8 | Low |
| 45220 | 4% | 1.4 ± 0.06 | 0.7 | Low |
| 45225 | 4% | 1.5 ± 0.06 | 0.8 | Low |
| 45205 | 4% | 1.7 ± 0.06 | 0.8 | Low |
| 45202 | 4% | 1.3 ± 0.06 | 0.7 | Low |
| 45214 | 4% | 1.3 ± 0.06 | 0.7 | Low |
| 45229 | 4% | 1.3 ± 0.06 | 0.7 | Low |
| 45227 | 3% | 1.4 ± 0.07 | 0.8 | Low |
| 45213 | 3% | 1.4 ± 0.06 | 0.8 | Low |
| 45233 | 3% | 2.1 ± 0.05 | 1.2 | Moderate |
| 45206 | 3% | 1.3 ± 0.06 | 0.7 | Low |
| 45209 | 3% | 1.3 ± 0.06 | 0.8 | Low |
| 45216 | 3% | 1.5 ± 0.05 | 0.8 | Low |
| 45219 | 2% | 1.4 ± 0.06 | 0.8 | Low |
| 45203 | 2% | 1.3 ± 0.07 | 0.8 | Low |
| 45207 | 2% | 1.4 ± 0.07 | 0.7 | Low |
| 45239 | 2% | 1.9 ± 0.06 | 1.1 | Low |
| 45217 | 1% | 1.6 ± 0.06 | 0.8 | Low |
| 45267 | <1% | — | — | no model |
Testing help in Ohio
Ohio's radon program page is at odh.ohio.gov; it lists testing and certified-mitigator guidance. 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.
Cincinnati radon questions
- Is radon high in Cincinnati, Ohio?
- Low. Averaging the model's ZIP-code predictions across Cincinnati (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.6 pCi/L - close to the US average of 1.8 and about 45% below the Ohio average of 2.8. That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Cincinnati ranks 22 of 27 Ohio cities on this site.
- Which Cincinnati ZIP codes have the highest radon?
- Predictions for the 27 modeled ZIP codes in Cincinnati range from 1.3 to 2.1 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 4% 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 Cincinnati?
- Yes, once. The EPA recommends testing every home regardless of area. A short-term kit costs little and settles the question for your house; Cincinnati's low predicted average describes the typical home, not yours.
- What does EPA Radon Zone 1 mean for Cincinnati?
- Cincinnati sits mainly in Hamilton 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 1.6 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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