How do I test for radon in my home?

Easiest method: buy a short-term test kit ($15-$30) from a hardware store or online. Place it in the lowest livable area (basement or ground floor), closed windows, for 2-7 days. Mail it to the lab. Results in 1-2 weeks. For more accuracy: use a long-term test (90+ days, $25-$50). For real-time monitoring: a continuous radon monitor ($100-$200) gives ongoing readings. For real estate transactions: hire a certified radon measurement professional ($150-$300). The EPA recommends every home be tested, regardless of location or construction type.

What radon level is dangerous?

The EPA recommends mitigation at 4 pCi/L or higher. The WHO recommends action at 2.7 pCi/L. There is no known safe level of radon (any exposure carries some risk). Average indoor level in the U.S.: 1.3 pCi/L. Average outdoor level: 0.4 pCi/L. About 1 in 15 U.S. homes has levels at 4+ pCi/L. Even at 2-4 pCi/L, consider mitigation if you plan to stay in the home long-term, especially if there are smokers in the household (radon + smoking multiplies cancer risk significantly).

How much does radon mitigation cost?

Sub-slab depressurization (the most common method): $800-$2,500, average around $1,200. This is a one-time installation cost. Annual operating cost: $50-$100 (fan electricity). Reduces radon by 80-99%. The system runs continuously and requires minimal maintenance (check the fan annually, replace every 5-10 years at $150-$300). Other costs: retest after installation ($15-$50 DIY or $150-$300 professional) to verify the system is working. The investment is modest compared to the health risk.

Does every home have radon?

Every home has SOME radon (it occurs naturally in all soil). The question is whether levels are high enough to pose a health risk. About 1 in 15 U.S. homes has radon at 4+ pCi/L (the EPA action level). Radon levels vary widely — even neighboring homes can have very different levels. High-risk areas: the northern half of the U.S. generally has higher radon levels (EPA Zone 1), but elevated levels have been found in every state. The ONLY way to know your home's level: test it. Every home should be tested, regardless of location, age, or construction type.

Article

Home Improvement

Radon Guide: Testing, Mitigation & Health Risks

Lumberama Editorial Team, Home Safety & Indoor Air Quality Specialists Jun 21, 2026 12 min read

What Is Radon

Radon is a naturally occurring radioactive gas that comes from the breakdown of uranium in soil, rock, and water. It is colorless, odorless, and tasteless (you cannot detect it without testing). Radon enters homes through cracks in the foundation, gaps around pipes and wires, and through well water. It can accumulate to dangerous levels in any home, regardless of age, construction type, or location.

Health risk: Radon is the #1 cause of lung cancer among non-smokers and the #2 cause overall (after smoking). The EPA estimates radon causes about 21,000 lung cancer deaths per year in the U.S. The risk is proportional to the level and duration of exposure. There is no known safe level of radon, but the EPA recommends action at 4 picocuries per liter (pCi/L) or higher.

Testing

Short-term test (2-7 days): The quickest way to screen. Charcoal or alpha-track test kit placed in the lowest livable area (basement or ground floor) for 2-7 days, then mailed to a lab. Cost: $15-$30 for a DIY kit. Results in 1-2 weeks. Good for initial screening but less accurate than long-term testing (radon levels fluctuate daily and seasonally).

Long-term test (90+ days): Alpha-track or electret detector placed for 90 days to 1 year. Provides a more accurate average radon level. Cost: $25-$50 for a DIY kit. Recommended for a more representative measurement.

Continuous radon monitor: An electronic device that measures radon levels continuously and displays real-time readings. Cost: $100-$
2
0
Great for ongoing monitoring, especially after mitigation. Popular brands: Airthings, Safety Siren.

Professional testing: A certified radon measurement professional places and retrieves the test. Cost: $150-$
3
0
Required for real estate transactions in many states.

Understanding Results

Below 2 pCi/L: low risk (no action needed, but there is no truly safe level). 2-4 pCi/L: moderate (consider mitigation, especially if you plan to stay long-term). 4+ pCi/L: the EPA recommends mitigation. The average indoor radon level in the U.S. is 1.3 pCi/L. The average outdoor level is 0.4 pCi/L. About 1 in 15 U.S. homes has radon at 4+ pCi/L.

Mitigation

Sub-slab depressurization: The most common and effective method. A PVC pipe is inserted through the foundation slab into the gravel or soil beneath. A fan attached to the pipe draws radon from under the slab and vents it above the roof. Cost: $800-$2,500 (average $1,200). Reduces radon levels by 80-99%. Runs continuously (the fan uses about $50-$100/year in electricity).

Other methods: Sealing cracks and openings (helps but rarely sufficient alone). Sub-membrane depressurization (for crawl spaces — similar to sub-slab but under a plastic membrane). Heat recovery ventilator (HRV) — increases ventilation to dilute radon (less effective than sub-slab). Water treatment (for well water radon): aeration or granular activated carbon filter ($1,000-$5,000).