Is radon high in Marion County, Florida?

Low. The model predicts a long-term basement average of 1.5 pCi/L in Marion County (about 19% below the US average of 1.8 and about 1.2× the Florida average of 1.3). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 8 of 67 Florida counties.

Should I test for radon in Marion County?

Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Marion County already range from 1.2 to 1.7 pCi/L. A short-term kit costs little and settles the question for your house.

What does EPA Radon Zone 2 mean for Marion County?

Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.5 pCi/L does not line up with Zone 2, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.

How much does radon mitigation cost in Marion County?

A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Florida 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.

Radon levels in Marion County, Florida

LowEPA Zone 2

Predicted long-term basement average of 1.5 pCi/L (model estimate) across 23 ZIP codes - about 19% below the US average of 1.8, about 1.2× the Florida average of 1.3. Ranked #8 of 67 Florida counties.

Test Marion County, FL once anyway - radon varies house to house

The predicted basement average here is 1.5 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.

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

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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.

1.5 ± 0.07

pCi/L predicted basement mean (model SD)

1.4 ± 0.10

pCi/L predicted upstairs (above-ground) mean

1.2-1.7

range of ZIP-level basement predictions in the county

What this means for Marion

The typical Marion County home is predicted below 2 pCi/L, the lowest band. That is the best case an area can show - but it describes the average house, and the ZIP-level predictions within the county still span 1.2 to 1.7 pCi/L.

Note that the EPA classifies Marion County as Zone 2 while the newer model predicts 1.5 pCi/L. The zone map predates two decades of test data; where they disagree, we grade on the model but show both. County figures weight each ZIP by its 2010 Census population, so they describe where people live rather than empty land.

Comparable Florida counties: Alachua County (1.5), Taylor County (1.5), Union County (1.5), Madison County (1.5). The state's highest is Jefferson County at 1.6 pCi/L.

ZIP codes in Marion County

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

ZIP	Basement	Upstairs	Grade
34491	1.4 ± 0.07	1.2	Low
34472	1.4 ± 0.07	1.4	Low
34471	1.7 ± 0.06	2.7	Low
34482	1.5 ± 0.06	1.6	Low
34476	1.5 ± 0.06	1.2	Low
34480	1.7 ± 0.06	1.7	Low
34470	1.5 ± 0.07	2.4	Low
34481	1.3 ± 0.08	1.0	Low
34473	1.5 ± 0.06	1.1	Low
34420	1.6 ± 0.06	1.6	Low
34474	1.3 ± 0.07	1.4	Low
34479	1.4 ± 0.07	1.6	Low
34432	1.3 ± 0.08	1.0	Low
34475	1.5 ± 0.06	1.5	Low
32784	1.4 ± 0.07	0.8	Low
34488	1.2 ± 0.07	0.8	Low
32179	1.2 ± 0.08	0.8	Low
32134	1.3 ± 0.09	0.8	Low
34431	1.4 ± 0.08	0.9	Low
32113	1.4 ± 0.08	1.1	Low
32686	1.7 ± 0.06	1.7	Low
32617	1.6 ± 0.06	1.5	Low
32195	1.5 ± 0.06	0.9	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.

Marion County radon questions

Is radon high in Marion County, Florida?: Low. The model predicts a long-term basement average of 1.5 pCi/L in Marion County (about 19% below the US average of 1.8 and about 1.2× the Florida average of 1.3). That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Ranked 8 of 67 Florida counties.
Should I test for radon in Marion County?: Yes, once. The EPA recommends testing every home regardless of area, and the model's ZIP-level predictions in Marion County already range from 1.2 to 1.7 pCi/L. A short-term kit costs little and settles the question for your house.
What does EPA Radon Zone 2 mean for Marion County?: Zone 2 - moderate potential (2-4 pCi/L). The zone map dates from 1993 and classifies whole counties. The newer model's predicted average of 1.5 pCi/L does not line up with Zone 2, which is common - the EPA itself says high-radon homes exist in every zone. Neither replaces a test of your own home.
How much does radon mitigation cost in Marion County?: A standard active sub-slab depressurization system typically runs $800-$2,500 installed nationally; Florida 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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