Radon levels in Webster County, Iowa

HighEPA Zone 1

Predicted long-term basement average of 4.3 pCi/L (model estimate) across 13 ZIP codes - about 2.4× the US average of 1.8, about 1.2× the Iowa average of 3.5. Ranked #35 of 99 Iowa counties.

Test Webster County, IA now - and consider a continuous monitor

The model predicts a long-term basement average of 4.3 pCi/L here, at or above the EPA action level of 4. Homes in the same ZIP still vary widely, so a real test is the only way to know your number. A continuous digital monitor shows how your level swings with weather and season, which matters when you're near the action level.

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.

4.3 ± 0.06

pCi/L predicted basement mean (model SD)

2.5 ± 0.07

pCi/L predicted upstairs (above-ground) mean

3.7-4.4

range of ZIP-level basement predictions in the county

What this means for Webster

The typical home in Webster County is predicted to sit at or above the EPA action level of 4 pCi/L in the basement. In practice that means a large share of houses here would qualify for mitigation if tested, and buyers routinely ask for radon tests in Iowa transactions.

The 1993 EPA zone (1) and the 2001-2021 model agree for Webster. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable Iowa counties: Fremont County (4.3), Woodbury County (4.4), Humboldt County (4.3), Boone County (4.4). The state's highest is Sioux County at 6.3 pCi/L.

ZIP codes in Webster County

Predicted basement and upstairs means by ZIP (model estimate). ZIPs whose land is mostly in this county.

ZIPBasementUpstairsGrade
505014.4 ± 0.072.5High
505434.4 ± 0.052.7High
505304.3 ± 0.052.5High
505324.0 ± 0.062.4Moderate
505694.2 ± 0.052.5High
505573.9 ± 0.052.4Moderate
505164.2 ± 0.052.7High
505234.1 ± 0.052.6High
505244.1 ± 0.052.4High
505443.7 ± 0.062.2Moderate
505663.9 ± 0.052.4Moderate
505184.3 ± 0.062.4High
505944.0 ± 0.052.4Moderate

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.

Webster County radon questions

Is radon high in Webster County, Iowa?
High. The model predicts a long-term basement average of 4.3 pCi/L in Webster County (about 2.4× the US average of 1.8 and about 1.2× the Iowa average of 3.5). That is at or above the EPA action level of 4 pCi/L, so the typical home here would qualify for mitigation. Ranked 35 of 99 Iowa counties.
Should I test for radon in Webster County?
Yes, soon. With a predicted average of 4.3 pCi/L and at least one ZIP predicted at 4.4, many homes in Webster 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 1 mean for Webster County?
Zone 1 - highest potential (predicted average > 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 Webster County?
A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Iowa 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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