Radon Levels in Florida by Zip Code: A Guide
Florida has a reputation as a low-radon state, which leads many residents to assume the gas is not their problem. That assumption is risky. Searching radon levels in Florida by zip code surfaces averages that hide a lot of variation, and parts of the state, particularly the central phosphate region, see readings well above the EPA action level. This guide explains what zip-code-level radon data can and cannot tell you, where Florida’s hotspots are, and why a state-average reputation never substitutes for testing your own home. It summarizes EPA and state guidance current as of 2026 and is general information, not a substitute for a measurement.
Part of our Radon Levels guide — start there for the full picture →
Can you find radon levels in Florida by zip code?
To a degree, yes. State health departments and the EPA publish radon data aggregated by county and, in some cases, finer geographic areas. Florida’s Department of Health has historically tracked radon test results across the state, and county-level averages are available. True zip-code precision is harder to find and less reliable, because it depends on how many homes in that zip have been tested.
The key caveat is that these figures are averages of past tests, not predictions for your address. A zip code with a low average can still contain individual homes that test high. The data sets expectations; it does not measure your house.
Why Florida is not uniformly low
Florida’s overall radon profile is moderate, but it is far from uniform. Central Florida sits atop phosphate deposits that contain uranium, the parent material radon comes from. Counties in the phosphate belt, including areas around Polk, Hillsborough, and neighboring regions, have produced elevated readings. Coastal and southern areas generally run lower.
Building practices add another wrinkle. Florida homes are often built on concrete slabs, and slab cracks or gaps around plumbing can let soil gas in. The mix of geology and construction means a statewide “low radon” label oversimplifies a more varied reality.
What the EPA zone map says about Florida
On the EPA Map of Radon Zones, most of Florida falls into Zone 2 or Zone 3, the moderate and lower-risk categories, with some Zone 1 counties in the phosphate region. That places it below high-radon states like Colorado, but the same lesson applies everywhere: the map predicts county averages, not homes. Our broader guide to the EPA radon map explains how those zones are built and why they cannot replace testing.
For Florida residents, a Zone 2 or 3 designation is reassuring at the regional level but says nothing definitive about a specific property. High-radon homes exist in every zone.
The limits of zip-code data
Zip-code averages have three big weaknesses. First, sample size: if only a handful of homes in a zip have ever been tested, the average is statistically shaky. Second, variation within the zip: soil, foundation type, and construction differ house to house. Third, age of the data: older results may not reflect current housing stock or newer construction.
Because of these limits, treating a favorable zip-code number as proof your home is safe is a mistake. The EPA’s consistent message is that every home should be tested regardless of regional data. Zip-code figures are a backdrop, not an answer.
Why your individual home matters most
Radon entry is intensely local. It depends on the soil chemistry directly beneath your foundation, the cracks and gaps in that foundation, how tightly the home is sealed, and the pressure differences that pull soil gas indoors. Two homes in the same zip code can read very differently for these reasons.
This is why a Florida home in a low-average zip can still test above 4.0 pCi/L, and why a home in the phosphate belt might test lower than its neighbors. The only way to know your number is to test. Our guide on radon levels by zip code covers this national pattern in more detail.
How Florida testing compares to Colorado
Florida residents sometimes contrast their situation with higher-radon states. Colorado’s Front Range, for example, sits in Zone 1 with a large share of homes above the action level, so testing there is routine. Florida’s lower regional risk does not change the per-home recommendation, but it does mean a smaller fraction of Florida homes will need mitigation.
The practical takeaway is identical in both states: test, then act on your own number. The radon testing hub explains the process, which works the same regardless of which state’s average you started from.
How to test a Florida home
Testing is simple and inexpensive. Place a short-term test kit in the lowest livable level, away from drafts and high humidity, with windows closed before and during the test. Florida’s humidity makes following kit instructions on placement and conditions especially important. For a fuller picture, a long-term test over 90 days captures seasonal variation.
If the result is at or above 4.0 pCi/L, plan mitigation; if it is borderline, confirm with a second test. A favorable zip-code average is no reason to skip this step. Your home’s actual reading is the only figure that should drive a decision.
The phosphate belt and Florida’s radon hotspots
Central Florida’s elevated radon traces to its phosphate deposits. Phosphate rock contains uranium, and where it lies near the surface or has been disturbed by mining, the soil produces more radon. Counties in and around the phosphate-mining region have historically recorded the state’s higher readings. This is a clear example of geology, not climate or construction, driving radon potential.
Reclaimed mining land adds another wrinkle. In some areas, former phosphate lands were developed for housing, and the disturbed ground can have altered radon characteristics. Buyers in central Florida’s phosphate region have particular reason to test, because the regional average understates the variation within these zones. As always, the county or zip-code figure is a backdrop; the individual home’s reading is what matters.
What zip-code data is good for
Despite its limits, zip-code and county radon data has legitimate uses. It helps state programs target outreach and education to higher-risk areas. It gives relocating buyers a regional heads-up about what to expect. And it underscores, for residents of moderate states like Florida, that radon is not exclusively a northern or mountain-state concern. Used as a backdrop rather than a verdict, the data is genuinely informative.
The mistake is treating a favorable zip-code average as permission to skip testing your home. The data describes the past test results of other houses, often a small and aging sample, not a prediction for your specific address. The right mental model is the same one the EPA applies to its zone map: regional data sets expectations, while an individual test answers the only question that drives a decision. Both states and the federal government recommend testing every home regardless of local averages.
How Florida construction affects radon
Florida’s building styles influence how radon enters homes. Slab-on-grade construction is common, and cracks or gaps in a slab, around plumbing penetrations, or at the slab-wall joint provide pathways for soil gas. Homes without basements still get radon; the gas simply enters through the slab and ground-floor openings. Tightly built, air-conditioned homes can also concentrate radon because they exchange less air with the outdoors.
The humidity that defines Florida is relevant to testing rather than to radon levels themselves. High humidity can affect certain test devices, so following kit instructions on placement and conditions is especially important. The takeaway is that Florida’s construction does not exempt homes from radon; it simply changes the entry points. Slab homes in moderate-zone counties still test high often enough that testing remains the only reliable check.
Testing during a Florida home purchase
Radon may come up less often in Florida real-estate deals than in high-radon states, but buyers can and should request a test during the inspection period, especially in the central phosphate region. A short-term professional measurement under closed-house conditions fits the typical inspection timeline and gives a documented result both parties can rely on. The cost is small relative to the home price.
If a Florida test comes back above the action level, the same negotiation options apply as anywhere: the seller can mitigate or credit the buyer. Because Florida homes are usually slab-on-grade, mitigation often involves sub-slab depressurization adapted to the foundation. A favorable regional reputation is not a reason to waive a radon test on a home you are about to buy; the test protects you from inheriting an unknown that a zip-code average could never reveal.
Why Florida’s reputation can be misleading
Florida’s image as a low-radon state does real harm when it discourages testing. The statewide average is moderate, but averages bury the hotspots. A homeowner in the central phosphate region who skips testing because “Florida doesn’t have radon” may live in exactly the kind of area where elevated readings cluster. Reputation is a poor guide at the individual-home level.
The same reasoning applies in reverse to high-radon states. A Colorado homeowner cannot assume every home tests high any more than a Florida homeowner can assume every home tests low. Both are working from regional averages that say nothing definitive about a specific address. The reputation sets a backdrop expectation, useful, but not a substitute for measurement.
This is why public-health agencies push universal testing regardless of state or local reputation. The gas is invisible, the consequences are delayed, and the only reliable signal is a test. Trusting a state’s reputation over a measurement is precisely the gap that leaves some homes unprotected, in Florida’s phosphate belt as much as anywhere.
Why national data beats anecdote
Homeowners sometimes rely on what a neighbor or agent says about radon in the area, which is a poor substitute for data. Anecdotes reflect a handful of homes under unknown conditions, while aggregated state and EPA data reflect thousands of measurements and the underlying geology. Even so, the most reliable data describes averages, and averages do not predict your house.
The national pattern is consistent and worth respecting: radon is present everywhere, problematic in a meaningful minority of homes, and concentrated in certain geologies. Florida’s place in that pattern is moderate overall with real hotspots. Our broader guide on radon levels by zip code explains why zip-level data nationwide carries the same caveats it does in Florida.
A simple plan for any home, in any zip
The same plan works regardless of state or zip code. Test the home with a short-term kit under closed-house conditions in the lowest livable level, or use a long-term test for a fuller picture. Confirm borderline results near 4.0 pCi/L with a second test. If the level reaches the action threshold, plan mitigation; mitigation works the same way in Florida as in Colorado.
Whether you start from a low Florida zip average or a high Front Range one, the favorable or unfavorable regional number changes only your expectations, not the recommendation. Test, then act on your own result. The radon testing hub walks through the process, which is identical no matter which state’s data you began with.
Zip-code data is a helpful starting point and a poor finishing point. It tells you the neighborhood’s history; it cannot tell you what is happening under your own foundation right now. Treating the regional figure as a prompt to test, rather than a reason to skip testing, is the single most important habit for any homeowner reading radon data, in Florida or anywhere else.
References
- EPA Map of Radon Zones — U.S. Environmental Protection Agency
- Health Risk of Radon — U.S. Environmental Protection Agency
- Radon and Indoor Air — American Lung Association
Frequently asked questions
Can I look up radon levels in Florida by zip code?
County-level and some finer-grained averages are available through state health data and the EPA, but reliable zip-code precision is limited by how many homes have been tested. These figures are past averages, not predictions for your address.
Is radon a problem in Florida?
Florida is moderate overall, but not uniform. The central phosphate region, including areas around Polk and Hillsborough counties, can have elevated readings because the soil contains uranium. Every home should still be tested.
Does a low zip-code average mean my home is safe?
No. High-radon homes exist in every area, and radon entry depends on local soil and foundation conditions a zip-code average cannot capture. The EPA recommends testing every home regardless of regional data.
How do I test my Florida home for radon?
Place a short-term kit in the lowest livable level with windows closed, following the instructions, or use a long-term test for a fuller picture. If results reach 4.0 pCi/L or higher, plan mitigation.
Whether you are comparing Florida data or settling along the Colorado Front Range, you can connect with a vetted radon professional through our contact page for help testing and interpreting your results.
Test your home for radon
Radon is invisible and odorless, so a test is the only way to know your level. A short-term kit gives a first reading in days; a digital monitor tracks it over time.
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