Is radon high in Houston, Texas?

Low. Averaging the model's ZIP-code predictions across Houston (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.2 pCi/L - about 32% below the US average of 1.8 and about 19% below the Texas average of 1.5. That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Houston ranks 80 of 83 Texas cities on this site.

Which Houston ZIP codes have the highest radon?

Predictions for the 90 modeled ZIP codes in Houston range from 1.1 to 1.5 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 0% at or above 2. The city is fairly uniform, so the city-wide number is a reasonable guide for any neighborhood.

Should I test for radon in Houston?

Yes, once. The EPA recommends testing every home regardless of area. A short-term kit costs little and settles the question for your house; Houston's low predicted average describes the typical home, not yours.

What does EPA Radon Zone 3 mean for Houston?

Houston sits mainly in Harris County, which the EPA classifies as Zone 3 - low potential (< 2 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 Houston, Texas

LowEPA Zone 3

Predicted long-term basement average of 1.2 pCi/L (model estimate) across the 90 modeled ZIP codes in Houston - about 32% below the US average of 1.8, about 19% below the Texas average of 1.5. Ranked #80 of 83 Texas cities on this site. Most of the city lies in Harris County (its ZIPs also reach into 1 other county).

Test Houston, TX once anyway - radon varies house to house

The predicted basement average here is 1.2 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.

1.2 ± 0.07

pCi/L predicted basement mean (model SD)

0.5 ± 0.10

pCi/L predicted upstairs (above-ground) mean

1.1-1.5

range of ZIP-level basement predictions in the city

of Houston ZIPs predicted ≥ 4 pCi/L (0% ≥ 2)

What this means for Houston

The typical Houston home is predicted below 2 pCi/L, the lowest band. That describes the average house; the ZIP-level predictions inside the city still span 1.1 to 1.5 pCi/L.

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 (3) for Harris and the 2001-2021 model agree here.

Comparable Texas cities: McAllen (1.2), Harlingen (1.3), Brownsville (1.3), Pasadena (1.3).

ZIP codes in Houston

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
77032	3%	1.2 ± 0.07	0.5	Low
77077	3%	1.3 ± 0.07	0.5	Low
77084	3%	1.3 ± 0.06	0.6	Low
77034	3%	1.2 ± 0.07	0.5	Low
77339	3%	1.4 ± 0.06	0.6	Low
77043	2%	1.3 ± 0.07	0.6	Low
77048	2%	1.2 ± 0.07	0.5	Low
77045	2%	1.2 ± 0.08	0.6	Low
77075	2%	1.3 ± 0.07	0.5	Low
77082	2%	1.2 ± 0.07	0.5	Low
77013	2%	1.3 ± 0.07	0.6	Low
77017	2%	1.1 ± 0.07	0.5	Low
77028	2%	1.2 ± 0.07	0.5	Low
77016	2%	1.2 ± 0.07	0.5	Low
77020	1%	1.1 ± 0.07	0.5	Low
77029	1%	1.1 ± 0.08	0.5	Low
77047	1%	1.3 ± 0.07	0.6	Low
77078	1%	1.2 ± 0.07	0.6	Low
77088	1%	1.3 ± 0.07	0.5	Low
77092	1%	1.2 ± 0.07	0.5	Low
77345	1%	1.4 ± 0.06	0.7	Low
77007	1%	1.1 ± 0.07	0.4	Low
77015	1%	1.3 ± 0.07	0.6	Low
77036	1%	1.1 ± 0.07	0.5	Low
77044	1%	1.5 ± 0.07	0.6	Low
77051	1%	1.1 ± 0.07	0.5	Low
77061	1%	1.2 ± 0.07	0.6	Low
77079	1%	1.3 ± 0.07	0.4	Low
77093	1%	1.1 ± 0.06	0.6	Low
77338	1%	1.3 ± 0.07	0.6	Low
77396	1%	1.5 ± 0.07	0.6	Low
77450	1%	1.4 ± 0.06	0.6	Low
77018	1%	1.3 ± 0.07	0.5	Low
77041	1%	1.4 ± 0.06	0.6	Low
77055	1%	1.3 ± 0.07	0.5	Low
77059	1%	1.4 ± 0.06	0.7	Low
77072	1%	1.2 ± 0.07	0.5	Low
77089	1%	1.4 ± 0.07	0.6	Low
77091	1%	1.2 ± 0.07	0.6	Low
77008	1%	1.2 ± 0.07	0.4	Low
77009	1%	1.2 ± 0.07	0.5	Low
77021	1%	1.1 ± 0.07	0.5	Low
77024	1%	1.3 ± 0.07	0.4	Low
77026	1%	1.2 ± 0.07	0.5	Low
77042	1%	1.2 ± 0.07	0.6	Low
77080	1%	1.2 ± 0.07	0.5	Low
77087	1%	1.1 ± 0.07	0.5	Low
77022	1%	1.1 ± 0.07	0.5	Low
77033	1%	1.1 ± 0.07	0.6	Low
77035	1%	1.3 ± 0.07	0.6	Low
77062	1%	1.4 ± 0.07	0.6	Low
77074	1%	1.2 ± 0.07	0.5	Low
77096	1%	1.2 ± 0.07	0.6	Low
77099	1%	1.2 ± 0.07	0.5	Low
77004	1%	1.2 ± 0.07	0.5	Low
77023	1%	1.2 ± 0.08	0.5	Low
77040	1%	1.3 ± 0.07	0.5	Low
77054	1%	1.1 ± 0.07	0.5	Low
77085	1%	1.3 ± 0.07	0.5	Low
77053	1%	1.2 ± 0.07	0.6	Low
77076	1%	1.2 ± 0.07	0.5	Low
77489	1%	1.3 ± 0.06	0.6	Low
77012	1%	1.1 ± 0.07	0.5	Low
77025	1%	1.3 ± 0.07	0.6	Low
77057	1%	1.3 ± 0.07	0.5	Low
77058	1%	1.3 ± 0.07	0.6	Low
77060	1%	1.1 ± 0.07	0.5	Low
77063	1%	1.2 ± 0.07	0.5	Low
77064	1%	1.4 ± 0.06	0.6	Low
77598	1%	1.2 ± 0.07	0.5	Low
77011	1%	1.1 ± 0.07	0.5	Low
77019	1%	1.2 ± 0.07	0.5	Low
77056	1%	1.3 ± 0.07	0.5	Low
77070	1%	1.3 ± 0.07	0.5	Low
77071	1%	1.3 ± 0.06	0.6	Low
77081	1%	1.2 ± 0.07	0.5	Low
77003	1%	1.1 ± 0.07	0.5	Low
77027	1%	1.3 ± 0.06	0.5	Low
77031	1%	1.2 ± 0.07	0.6	Low
77090	1%	1.1 ± 0.07	0.5	Low
77006	<1%	1.2 ± 0.07	0.5	Low
77030	<1%	1.3 ± 0.07	0.6	Low
77038	<1%	1.2 ± 0.06	0.6	Low
77002	<1%	1.2 ± 0.07	0.5	Low
77005	<1%	1.4 ± 0.06	0.5	Low
77037	<1%	1.2 ± 0.08	0.5	Low
77067	<1%	1.2 ± 0.07	0.5	Low
77086	<1%	1.2 ± 0.07	0.6	Low
77098	<1%	1.2 ± 0.06	0.5	Low
77094	<1%	1.4 ± 0.07	0.6	Low
77204	<1%	—	—	no model
77010	<1%	—	—	no model
77046	<1%	—	—	no model

Testing help in Texas

We link only state program pages we could verify, and Texas'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.

Houston radon questions

Is radon high in Houston, Texas?: Low. Averaging the model's ZIP-code predictions across Houston (weighted by how much of the city each ZIP covers) gives a long-term basement mean of 1.2 pCi/L - about 32% below the US average of 1.8 and about 19% below the Texas average of 1.5. That is below the EPA's 2 pCi/L "consider fixing" threshold, though individual homes still vary. Houston ranks 80 of 83 Texas cities on this site.
Which Houston ZIP codes have the highest radon?: Predictions for the 90 modeled ZIP codes in Houston range from 1.1 to 1.5 pCi/L in the basement. 0% of them are predicted at or above 4 pCi/L and 0% at or above 2. The city is fairly uniform, so the city-wide number is a reasonable guide for any neighborhood.
Should I test for radon in Houston?: Yes, once. The EPA recommends testing every home regardless of area. A short-term kit costs little and settles the question for your house; Houston's low predicted average describes the typical home, not yours.
What does EPA Radon Zone 3 mean for Houston?: Houston sits mainly in Harris County, which the EPA classifies as Zone 3 - low potential (< 2 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.

← All Texas counties and cities · Harris County · How to test · Methodology