One of the most common questions homeowners ask is how radon is tested.
Because radon is a colorless, odorless, and tasteless radioactive gas, it cannot be detected by sight, smell, or taste. The only reliable way to determine whether a home or building has elevated radon levels is through testing.
Professional radon testing measures the concentration of radon gas inside a building over a specified period and helps determine whether mitigation is recommended.
Where Is the Test Performed?
Radon testing is typically conducted in the lowest occupiable level of the building. This may include:
- Basements
- Finished basements
- Crawlspaces (when designed for occupancy or as required by the testing protocol)
- First floors constructed on a slab
- Lower-level living areas
The goal is to measure the air occupants are most likely to breathe.
Types of Radon Tests
There are two primary types of radon testing.
Short-Term Testing
Short-term testing is commonly performed during:
- Real estate transactions
- Home inspections
- Initial screenings
- Property purchases
Most short-term tests remain in place for 48 hours to 7 days, depending on the testing device and protocol. These tests provide a quick indication of the property's radon level.
Long-Term Testing
Long-term testing generally lasts 90 days or longer. Because radon levels naturally fluctuate due to weather, temperature, barometric pressure, and ventilation, long-term testing provides a more accurate picture of the average annual radon concentration.
Long-term testing is often recommended when:
- Previous test results are borderline.
- Additional confirmation is desired.
- A homeowner wants a better understanding of year-round exposure.
Types of Radon Testing Equipment
Professional radon testing may utilize several different devices.
Continuous Radon Monitors (CRM)
Electronic instruments that continuously record radon concentrations throughout the testing period. These devices can also monitor:
- Temperature
- Humidity
- Barometric pressure
- Device movement
- Power interruptions
Continuous monitors are commonly used during real estate transactions because they provide detailed reports and can help identify possible test interference.
Passive Charcoal Devices
Activated charcoal devices absorb radon during the testing period. After the test is complete, the device is sent to an accredited laboratory for analysis. These are commonly used for residential screening tests.
Alpha Track Detectors
These devices are primarily used for long-term monitoring. They remain in the building for several months and provide an average radon concentration over an extended period.
Preparing for a Radon Test
For accurate results, buildings should typically remain under closed-building conditions before and during many short-term tests. This generally means:
- Exterior doors remain closed except for normal entry and exit.
- Windows remain closed.
- Whole-house fans are not operated.
- HVAC systems operate under normal conditions.
Following proper testing protocols helps ensure the results accurately represent indoor radon concentrations.
Understanding the Results
Radon concentrations are reported in picocuries per liter (pCi/L). According to the U.S. Environmental Protection Agency (EPA):
- Below 2.0 pCi/L — generally considered low, though no level of radon exposure is completely risk-free.
- Between 2.0 and 4.0 pCi/L — consider discussing mitigation options, especially if long-term exposure is expected.
- 4.0 pCi/L or higher — the EPA recommends taking action to reduce radon levels.
A qualified radon professional can explain your results and recommend whether additional testing or mitigation is appropriate.
What Happens If Radon Levels Are High?
If elevated radon levels are identified, a radon mitigation system can usually reduce indoor concentrations. A typical mitigation system may include:
- PVC vent piping
- An in-line radon fan
- Sealing accessible foundation openings
- Venting radon gas safely above the roofline
After installation, a follow-up radon test should be performed to verify that the mitigation system is effectively reducing indoor radon levels.
Frequently Asked Questions
- Can I test for radon myself?
- Yes. Homeowners can purchase do-it-yourself radon test kits from home improvement stores or online retailers. However, professional testing may provide greater confidence through calibrated equipment, standardized testing procedures, and detailed reporting, particularly for real estate transactions or when documentation is needed.
- How often should I test my home?
- The EPA recommends testing every home at least once. Additional testing is recommended after installing a mitigation system, completing major renovations, finishing a basement, or making significant changes to the building's ventilation or foundation.
- Can radon levels change over time?
- Yes. Radon levels naturally fluctuate due to seasonal weather patterns, barometric pressure, soil moisture, ventilation, and changes to the building. A home that tested low several years ago may benefit from retesting, especially after renovations or structural modifications.
- Is one test enough?
- For many situations, a properly conducted test provides sufficient information. However, if results are near the EPA action level or if long-term exposure is a concern, additional or long-term testing may be recommended.
How Axis Remedial Sciences Can Help
Axis Remedial Sciences provides professional radon testing, radon mitigation consulting, indoor air quality assessments, and environmental consulting for residential, commercial, educational, healthcare, and government facilities.
- Short-Term Radon Testing
- Long-Term Radon Testing
- Real Estate Transaction Testing
- Radon Mitigation Consulting
- Post-Mitigation Verification Testing
- Indoor Air Quality Assessments
With more than 20 years of environmental consulting experience, we use accepted testing protocols and provide clear reporting and practical recommendations. Contact Axis Remedial Sciences today to schedule a professional radon test.
Serving Tennessee, Georgia, and Alabama.