Radon levels in Warren County, Missouri
ModerateEPA Zone 2Predicted long-term basement average of 2.0 pCi/L (model estimate) across 5 ZIP codes - close to the US average of 1.8, close to the Missouri average of 2.2. Ranked #94 of 115 Missouri counties.
Test Warren County, MO - the EPA says "consider fixing" in this range
The predicted basement average here is 2.0 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. How the numbers work.
2.0 ± 0.13
pCi/L predicted basement mean (model SD)
1.3 ± 0.07
pCi/L predicted upstairs (above-ground) mean
1.9-2.2
range of ZIP-level basement predictions in the county
What this means for Warren
The typical Warren County 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 roughly one home in several in a moderate area will test above 4.
The 1993 EPA zone (2) and the 2001-2021 model agree for Warren. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.
Comparable Missouri counties: Phelps County (2.0), Reynolds County (2.0), Adair County (2.1), Perry County (2.1). The state's highest is Atchison County at 4.4 pCi/L.
ZIP codes in Warren County
Predicted basement and upstairs means by ZIP (model estimate). ZIPs whose land is mostly in this county.
| ZIP | Basement | Upstairs | Grade |
|---|---|---|---|
| 63383 | 1.9 ± 0.19 | 1.2 | Low |
| 63390 | 2.2 ± 0.10 | 1.3 | Moderate |
| 63357 | 2.1 ± 0.06 | 1.4 | Moderate |
| 63351 | 2.1 ± 0.07 | 1.3 | Moderate |
| 63381 | 1.9 ± 0.06 | 1.1 | Low |
If your test comes back at 4 pCi/L or higher
Mitigation is a routine job: a fan-driven pipe that vents soil gas from under the slab to above the roofline, typically $800-$2,500 installed (typical range; local quotes vary). Use certified professionals: EPA find-a-professional. Read the full mitigation guide.
Warren County radon questions
- Is radon high in Warren County, Missouri?
- Moderate. The model predicts a long-term basement average of 2.0 pCi/L in Warren County (close to the US average of 1.8 and close to the Missouri average of 2.2). That is in the 2-4 pCi/L range where the EPA recommends considering mitigation. Ranked 94 of 115 Missouri counties.
- Should I test for radon in Warren County?
- Yes, soon. With a predicted average of 2.0 pCi/L, many homes in Warren County will test above the 4 pCi/L action level. Use a short-term kit first; if it reads 2 or higher, confirm with a long-term test or continuous monitor before deciding on mitigation.
- What does EPA Radon Zone 2 mean for Warren County?
- Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The 2001-2021 model agrees with the zone here. Neither replaces a test of your own home.
- How much does radon mitigation cost in Warren County?
- A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Missouri quotes vary with foundation type (slab, crawlspace, basement), home size and local labor. Get two or three bids from certified mitigators listed by your state radon program or the EPA's find-a-professional page.
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