Is radon high in Topeka, Kansas?

Moderate. Averaging the model's ZIP-code predictions across Topeka (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 2.2 pCi/L - about 1.2× the US average of 1.8 and about 15% below the Kansas average of 2.6. That is in the 2-4 pCi/L range where the EPA says to consider fixing. Topeka ranks 8 of 10 Kansas cities on this site.

Which Topeka ZIP codes have the highest radon?

Predictions for the 17 modeled ZIP codes in Topeka range from 1.7 to 3.0 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 59% at or above 2. That spread is why the ZIP table below matters more than the city-wide number.

Should I test for radon in Topeka?

Yes, soon. With a predicted basement average of 2.2 pCi/L, a meaningful share of Topeka 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 2 mean for Topeka?

Topeka sits mainly in Shawnee County, which the EPA classifies as Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and covers whole counties. The 2001-2021 model agrees with the zone for the city. Neither replaces a test of your own home.

Radon levels in Topeka, Kansas

ModerateEPA Zone 2

Predicted long-term basement average of 2.2 pCi/L (model estimate) across the 17 modeled ZIP codes in Topeka - about 1.2× the US average of 1.8, about 15% below the Kansas average of 2.6. Ranked #8 of 10 Kansas cities on this site. Most of the city lies in Shawnee County.

Test Topeka, KS - the EPA says "consider fixing" in this range

The predicted basement average here is 2.2 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.

Get a short-term test kit →Or track it with 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.

2.2 ± 0.07

pCi/L predicted basement mean (model SD)

1.4 ± 0.08

pCi/L predicted upstairs (above-ground) mean

1.7-3.0

range of ZIP-level basement predictions in the city

of Topeka ZIPs predicted ≥ 4 pCi/L (59% ≥ 2)

What this means for Topeka

The typical Topeka 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). The 1993 EPA zone (2) for Shawnee and the 2001-2021 model agree here.

Comparable Kansas cities: Lawrence (2.1), Shawnee (2.3), Lenexa (2.4), Overland Park (2.5).

ZIP codes in Topeka

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
66614	12%	2.4 ± 0.08	1.5	Moderate
66604	11%	2.2 ± 0.06	1.4	Moderate
66605	9%	3.0 ± 0.07	1.7	Moderate
66606	9%	2.0 ± 0.09	1.4	Moderate
66609	9%	2.0 ± 0.10	1.3	Low
66607	9%	2.0 ± 0.07	1.3	Moderate
66608	7%	1.8 ± 0.07	1.1	Low
66616	7%	1.8 ± 0.08	1.1	Low
66618	6%	2.0 ± 0.06	1.2	Low
66611	5%	2.5 ± 0.08	1.7	Moderate
66610	4%	1.9 ± 0.08	1.2	Low
66615	3%	2.1 ± 0.05	1.2	Moderate
66617	2%	2.3 ± 0.06	1.3	Moderate
66612	2%	1.7 ± 0.07	0.9	Low
66603	2%	1.7 ± 0.06	1.0	Low
66619	2%	2.0 ± 0.07	1.1	Moderate
66546	1%	2.2 ± 0.07	1.4	Moderate
66621	<1%	—	—	no model
66622	<1%	—	—	no model

Testing help in Kansas

We link only state program pages we could verify, and Kansas's did not respond when we checked, so start from the 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.

Topeka radon questions

Is radon high in Topeka, Kansas?: Moderate. Averaging the model's ZIP-code predictions across Topeka (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 2.2 pCi/L - about 1.2× the US average of 1.8 and about 15% below the Kansas average of 2.6. That is in the 2-4 pCi/L range where the EPA says to consider fixing. Topeka ranks 8 of 10 Kansas cities on this site.
Which Topeka ZIP codes have the highest radon?: Predictions for the 17 modeled ZIP codes in Topeka range from 1.7 to 3.0 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 59% at or above 2. That spread is why the ZIP table below matters more than the city-wide number.
Should I test for radon in Topeka?: Yes, soon. With a predicted basement average of 2.2 pCi/L, a meaningful share of Topeka 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 2 mean for Topeka?: Topeka sits mainly in Shawnee County, which the EPA classifies as Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and covers whole counties. The 2001-2021 model agrees with the zone for the city. Neither replaces a test of your own home.

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