Texas — 7.3M metro

Radon in Houston,
TX

Houston and Harris County fall in EPA Zone 3 (low risk). Texas's Gulf Coast geology features deep sedimentary deposits with very low uranium content. The Texas Department of State Health Services reports Houston as one of the nation's lower-risk major metros for radon.

Risk Level

Low Risk

0.4–1.5 pCi/L

Typical range (area avg.)

EPA action level: 4 pCi/L

Why Houston Has Low Risk Radon

Houston sits on Quaternary marine and alluvial sediments that have been repeatedly washed clean of uranium-bearing minerals. The heavy clay soils (Houston's famous 'black gumbo') also act as barriers to radon migration, unlike the permeable soils of higher-risk regions.

Local Housing and Radon Risk

Houston's slab-on-grade construction dominates — virtually no full basements in flood-prone Houston. This dramatically reduces radon risk compared to cities with basement-heavy housing. However, homes in far western Houston suburbs in the Hill Country foothills may see higher readings.

Testing Advice for Houston Residents

While Houston's radon risk is low, testing is inexpensive and still recommended by EPA for all homes. Focus on homes in far western suburbs (Katy, Sugar Land areas bordering Waller County) where Hill Country geology begins to influence soil composition.

How to Test Your Houston Home

Step 1: Choose Your Test Type

For initial screening, a charcoal short-term test kit ($12–$25) placed for 48–96 hours provides a quick result. For the most accurate reading, a long-term alpha-track test ($20–$35) left in place for 90+ days accounts for seasonal variation — especially important in Houston's climate.

Step 2: Place the Test Correctly

Test in your lowest livable level — basement if you have one, otherwise the first floor. Keep the test 20 inches from the floor, away from windows and exterior walls. Close windows and doors 12 hours before and during the test for accurate results.

Step 3: Interpret Your Results

Below 2 pCi/L: low concern, retest every 2 years. 2–4 pCi/L: consider mitigation, retest in 2 years. 4 pCi/L or higher: the EPA recommends mitigation. Above 8 pCi/L: prioritize mitigation promptly.

Step 4: Hire a Certified Mitigator if Needed

If your test result is at or above 4 pCi/L, hire a certified radon mitigator. In Texas, always verify your contractor's state certification. Sub-slab depressurization — the most effective mitigation method — typically costs $800–$1,500 installed in the Houston area.

Frequently Asked Questions — Radon in Houston

Is radon a real problem in Houston?

Yes. Houston and Harris County fall in EPA Zone 3 (low risk). Texas's Gulf Coast geology features deep sedimentary deposits with very low uranium content. The Texas Department of State Health Services reports Houston as one of the nation's lower-risk major metros for radon. The EPA recommends all homes be tested regardless of location — radon levels can vary significantly even between neighboring properties.

How much does radon mitigation cost in this area?

In the Houston area, professional radon mitigation (sub-slab depressurization) typically costs $800–$1,500 installed. This is a one-time cost that reduces radon by 50–99%. The system requires minimal maintenance and a mitigator can typically complete the work in 3–5 hours.

Should I test if I have a new home?

Absolutely. New homes built with radon-resistant features still show elevated levels in testing — construction conditions and local geology vary too much to assume any home is safe. Test within the first year of occupancy, especially if your home has a basement.

Can I test radon myself, or do I need a professional?

DIY testing is reliable and recommended as a first step. Short-term kits ($12–$25) and long-term kits ($20–$35) are accurate when placed and returned correctly. Professional testing is only required for real estate transactions in some states. If your DIY test shows elevated levels, use a certified professional for both confirmation testing and mitigation.