Radon is a naturally occurring, invisible, odorless radioactive gas that seeps into homes from the ground. It is the second leading cause of lung cancer in the United States (after smoking), causing an estimated 21,000 deaths annually.
10 steps across 1 sections
1. Steps Guide
- Understand the risk — Radon enters homes through foundation cracks, gaps around pipes, sump pits, and any opening where soil meets the structure. All homes can have radon, regardless of age, type, ...
- Choose a testing method — Short-term test kits (charcoal canisters, 2-7 days, $10-$30) provide a screening result. Long-term test kits (alpha track detectors, 90+ days, $25-$50) provide a more accu...
- Prepare for testing — Close all windows and doors for 12 hours before starting the test and keep them closed during the test (except for normal entry/exit). This is called "closed-house conditions"...
- Place the test correctly — Test in the lowest livable level of the home (typically the basement or first floor). Place the detector at breathing height (2-6 feet) in a room that is regularly used. ...
- Conduct the test — For short-term kits: leave in place for the recommended period (minimum 48 hours), then seal and mail to the lab. For long-term tests: leave for 90+ days for the most accurate an...
- Interpret results — Results are reported in pCi/L (picocuries per liter). EPA action level: 4.0 pCi/L or above. Consider mitigation at 2.0-4.0 pCi/L. Average outdoor level: 0.4 pCi/L. Average indoo...
- Confirm elevated results — If a short-term test shows 4.0+ pCi/L, conduct a follow-up test (either another short-term or a long-term test) to confirm. If the average of two tests is 4.0+, proceed w...
- Hire a qualified mitigator — Look for NRPP (National Radon Proficiency Program) or NRSB (National Radon Safety Board) certified professionals. Get 2-3 quotes. Verify references and insurance.
- Install a mitigation system — The most effective method is sub-slab depressurization (SSD): a pipe inserted through the foundation slab connected to a fan that draws radon from under the house and ...
- Test after mitigation — Retest 24+ hours after the mitigation system is installed and operating. Levels should drop to below 2.0 pCi/L. Continue testing every 2 years to verify the system remains e...
Common Mistakes
- Assuming new homes are radon-free
- Testing in the wrong location
- Not maintaining closed-house conditions
- Relying on a neighbor's results
- Ignoring moderately elevated levels
Pro Tips
- Test before finishing a basement
- Include radon testing in home purchases
- Check for state-specific programs
- Monitor continuously
- Radon-resistant new construction (RRNC)