Skip to content
$5

County radon report

Get it

Locations and reports

Radon Levels in Harris County, Texas

Zone 3Lower predicted potential1,778 square miles · 7 bordering counties

What this means for you

  • Your area: EPA rates Harris County Zone 3, the lowest of its three radon zones. That is a prediction for the whole county, and homes with elevated levels occur in all three zones.
  • Local tests: Of 733 radon tests reported to CDC for Harris County (2008 to 2017), 2.9% were at or above 4 pCi/L, EPA's action level.
  • Your home: The only way to know your home’s level is to test it.

pCi/L (picocuries per liter) is the unit radon is measured in. EPA recommends fixing a home at 4 pCi/L or above, its action level.

Over the 2008 to 2017 laboratory totals, 2.9% of the radon tests reported to CDC for Harris County, Texas came back at or above the EPA action level of 4 pCi/L, and the median result was 0.4 pCi/L. EPA's Map of Radon Zones places the county in Zone 3, lower predicted potential. Radon levels vary from home to home, so only a test measures the level in yours.

Predicted: EPA radon zone

EPA Zone 3: lower predicted potential

EPA predicts an average indoor of less than 2 pCi/L (less than 75 Bq/m³) across the county as a whole.

This is a county-level geologic prediction. It is not a measurement of any address, and houses with elevated radon are found in all three zones.

USGS geologic potential: High across 100% of the county's land area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Harris County, 2008 to 2017, laboratory

Tests reported
733
At or above 4 pCi/L
2.9%
Median result
0.4 pCi/L
Reported results by concentration band, Harris County, 2008 to 2017, laboratory
Under 2 pCi/L: 95%2 to 4 pCi/L: 2%4 pCi/L and above: 3%

Of 733 pre-mitigation tests reported to CDC, not homes in this area. CDC publishes the share in each band, not a count per band, so the per-band counts in the table are calculated by Radon411 and rounded to add up to the published total.

Reported results by concentration band, Harris County, 2008 to 2017, laboratory: data table
Result bandTests Calculated by Radon411Share Measured
Under 2 pCi/L69895.2%
2 to 4 pCi/L141.9%
4 pCi/L and above212.9%

Distribution of tested buildings, not this house. People testing before a sale, or because they suspect a problem, are over-represented in any reported testing data.

Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

Harris County, In figures

Harris County in figures

What the published data says about Harris County, in words. A zone and a share of tests describe an area, never the level in any one home.

    • Predicted

      Predicted

      EPA places Harris County in Zone 3, lower predicted potential, as it does 214 other counties of Texas's 254.

      Of the 7 bordering counties, EPA places Brazoria County, Chambers County, Fort Bend County, Galveston County, Liberty County, Montgomery County and Waller County in Zone 3.

  • Reported tests

    Measured

    CDC publishes no annual figure for Harris County; its figure is a laboratory total for 2008 to 2017: 2.9% of 733 reported tests were at or above 4 pCi/L.

  • Local record

    Texas's radon program is the Texas Radon Group, run by Texas Tech University; its contacts are under Local resources.

    The county's largest incorporated places are Houston, Pasadena and Pearland; the figures here cover them as part of the county.

Harris County, Comparison

How Harris County compares

Measured

Harris County's own published CDC figures beside those of the counties that border it, for the same period.

Share of reported tests at or above 4 pCi/L

Measured

2008 to 2017, laboratory, highest first. Each county’s own published CDC figure.

  1. Brazoria CountyTX32 tests6.3%
  2. Montgomery CountyTX188 tests3.2%
  3. Fort Bend CountyTX105 tests2.9%
  4. Harris CountyThis page733 tests2.9%
  5. Chambers CountyTX3 tests0.0%
  6. Galveston CountyTX73 tests0.0%
  7. Liberty CountyTX1 test0.0%
  8. Waller CountyTX7 tests0.0%

Median reported result

Measured

2008 to 2017, laboratory, highest first. Each county’s own published CDC figure.

  1. Liberty CountyTX1 test1.2 pCi/L
  2. Montgomery CountyTX188 tests0.8 pCi/L
  3. Harris CountyThis page733 tests0.4 pCi/L
  4. Brazoria CountyTX32 tests0.3 pCi/L
  5. Fort Bend CountyTX105 tests0.2 pCi/L
  6. Galveston CountyTX73 tests0.2 pCi/L
  7. Chambers CountyTX3 tests0.1 pCi/L
  8. Waller CountyTX7 tests0.1 pCi/L

Each figure is that county’s own published CDC figure for 2008 to 2017, laboratory, counting radon tests reported to CDC, not homes. Harris County is this page. Nothing is averaged or combined across counties. The test count beside each county is CDC’s published number of pre-mitigation tests behind its figures. Figures from few tests can swing widely from year to year. Every Texas county’s own figure is in the Texas county table.

CDC publishes this figure only for counties here, so there is no state or national number to compare Harris County, Texas with.

Harris County, Bordering counties

Counties bordering Harris County

Calculated by Radon411

Harris County, Local resources

Local resources in Texas

Who to ask in Texas: the state's radon program, test kits and professionals.

Texas Radon Group

Texas Tech University

Texas’s radon program answers questions about testing, mitigation and the rules where you live.

Licensing of radon professionals
There are no radon certification requirements for the State of Texas at this time, but the National Radon Proficiency Program lists radon testers and mitigators within Texas that have passed a rigorous national certification program.
Visit the program's page(opens in a new tab)

Test kits

The program says: The Texas Radon Group offers free radon test kits for Texas individuals who qualify.

Radon professionals

3 professionals are listed in Texas.

Professionals in Texas

Harris County, Cities and towns

Cities and towns in Harris County

The radon figures on this page are for Harris County as a whole. They do not differ by city or town.

  • Houston (part)
  • Pasadena
  • Pearland (part)
  • League City (part)
  • Baytown (part)
  • Missouri City (part)
  • Friendswood (part)
  • La Porte
  • Deer Park
  • Katy (part)
  • Stafford (part)
  • Bellaire
  • Humble
  • South Houston
  • Tomball (part)
  • West University Place
  • Seabrook (part)
  • Webster
  • Galena Park
  • Jacinto City
  • Jersey Village
  • Waller (part)
  • Nassau Bay
  • Hunters Creek Village
The other 10 places in Harris County
  • Spring Valley Village
  • Bunker Hill Village
  • Taylor Lake Village
  • Piney Point Village
  • El Lago
  • Hedwig Village
  • Southside Place
  • Shoreacres (part)
  • Hilshire Village
  • Morgan's Point (part)

34 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county.

Harris County, Questions

Questions about radon in Harris County

Common questions8 questions, answered from the figures above

Are radon levels high in Harris County?

In 2017, 2.9% of the radon tests reported to CDC for Harris County, Texas were at or above 4 pCi/L, and the median reported pre-mitigation result was 0.4 pCi/L. That is a share of reported tests, not of homes. EPA places Harris County in Zone 3, lower predicted potential, a predicted average indoor screening level less than 2 pCi/L. Homes with elevated levels occur in all three zones, so the figures describe the area, not your house. Testing is the only way to know the radon level in a specific building.

What a radon level meansRadon in Texas

How do I get a radon test in Harris County?

EPA says you can test your home yourself or hire a qualified radon test company, and that either approach takes only a small amount of time and effort. No certified tester listed on Radon411 names Harris County as a service area yet. The Texas radon program is the place to ask about certified testers and any test kit offer it runs.

How to test a homeTest kits comparedFree and low-cost kits by stateTexas radon program

Who does radon mitigation in Harris County?

No listed mitigator names Harris County as a service area yet; the Texas directory lists 3 companies. EPA recommends having a qualified contractor fix a home with a radon problem, because lowering high radon levels takes technical knowledge and special skills, and some states require the work to be done by a licensed or certified professional. Your state radon program is the place to check whether Texas requires one.

How radon mitigation worksWhat mitigation costsMitigators in Texas

What EPA radon zone is Harris County in?

EPA places Harris County, Texas in Zone 3, which EPA describes as lower predicted potential for the area. A zone is a prediction for the whole county and never determines whether a particular home should be tested. EPA recommends testing every home regardless of zone.

Should I test my home in Harris County?

Yes. Testing is the only way to know the radon level in a specific building. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. How to test a home.

When is the best time of year to test?

EPA says short-term tests stay in the home from 2 to 90 days and that all radon tests should run a minimum of 48 hours; long-term tests stay more than 90 days. EPA's guides do not name a best season: they say radon levels tend to vary from day to day and season to season, so a long-term test is more likely than a short-term test to tell you the year-round average.

What does it cost to test?

EPA's Citizen's Guide calls testing easy and inexpensive, and EPA's Home Buyer's and Seller's Guide says passive short-term and long-term devices are generally inexpensive, while active devices may cost more. No national average price is published for this, so Radon411 does not give one. What testing costs.

Which counties border Harris County?

Harris County borders 7 counties, derived from Census county geometry. Radon potential follows geology rather than county lines, so a bordering county's report can be relevant.

What these figures mean if you own, buy, sell or rent

The reported-test figures on this page describe Harris County, Texas in 2017. They describe tests other people carried out in other buildings, and none of them measures yours.

  • If you own your home

    Test the lowest lived-in level; a short-term kit screens in days, a long-term kit reflects the year.

    How to test a home
  • If you are buying

    Ask for past results and any system's post-mitigation test, and test during the sale.

    Buying a house: radon guide
  • If you are selling

    Testing before you list puts the timing in your hands; disclosure rules differ by state.

    Selling a house: radon guide
  • If you rent, or rent out a home

    A tenant can test; a fix is the owner's to make, and duties differ by state.

    Radon in rental homes

How long a test has to run, under what conditions, and what EPA says a result means: the testing standard, in full.

Harris County, Products

Testing and mitigation products

Whatever the figures for Harris County show, only a test tells you about one home.

Harris County / Next steps

What to do next

Informational. Follow EPA guidance. EPA says all radon tests should be taken for a minimum of 48 hours, with windows and doors closed from 12 hours before a short-term test.