How much does radon mitigation cost?

Average: $800-$2,500 (most homeowners pay $1,200-$1,500). Sub-slab depressurization (most common): $800-$2,500. Crawl space (sub-membrane): $800-$2,500. Heat recovery ventilator: $1,500-$3,000. Factors: home size, foundation type, number of suction points needed, local labor rates. Ongoing cost: $50-$100/year in electricity. Fan replacement: $100-$300 every 5-10+ years. ROI: protects your family from the second leading cause of lung cancer.

What is a safe level of radon?

EPA action level: 4 pCi/L (picocuries per liter). Mitigation recommended at or above 4 pCi/L. WHO recommends action at 2.7 pCi/L. Average indoor radon level: 1.3 pCi/L. Average outdoor level: 0.4 pCi/L. Important: there is no truly safe level of radon. Any exposure carries some risk. The EPA recommends considering mitigation even between 2-4 pCi/L. After mitigation: most systems reduce levels to below 2 pCi/L.

How do I test my home for radon?

Easiest: buy a DIY test kit ($10-$30) from a hardware store or online. Short-term test: place in lowest livable level for 2-7 days. Mail to lab for results. Long-term test (90+ days): more accurate, accounts for seasonal variation. Professional test: $100-$300. Uses continuous monitor. Results in 48 hours. Required for real estate transactions in many areas. Tips: test in the lowest livable area. Keep windows and doors closed during the test (except normal entry/exit). Do not place near drafts, windows, or high humidity. Every home should be tested regardless of age or location.

Does every home need radon testing?

Yes. The EPA recommends testing every home. Radon levels vary house to house. A neighbor's test result does not predict yours. Radon can be high in any state, any county, any neighborhood. New homes can have high radon. Old homes can have low radon. Geography matters (some areas have higher average levels) but it is not a reliable predictor for individual homes. Test when: before buying (part of home inspection). If you have never tested. Every 2 years. After major renovations. After installing a mitigation system (to verify it works). Cost of testing: $10-$30 DIY. $100-$300 professional. Cost of not testing: potentially your health.

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Home Improvement

Radon Guide: Testing, Mitigation & Cost

Lumberama Editorial Team, Indoor Air Quality & Home Safety Specialists Nov 15, 2026 8 min read

What Is Radon?

Radon is a naturally occurring radioactive gas. Colorless, odorless, tasteless — you cannot detect it without testing. Produced by the natural decay of uranium in soil, rock, and groundwater. Enters homes through cracks in foundations, gaps around pipes, and other openings.

Health risks: Second leading cause of lung cancer in the US (after smoking). Causes approximately 21,000 lung cancer deaths per year. Risk increases with higher radon levels and longer exposure. Smokers exposed to radon have a much higher risk.

EPA action level: 4 pCi/L (picocuries per liter). Mitigation recommended at or above this level. WHO recommends action at 2.7 pCi/L. Any level of radon carries some risk, but risk increases with concentration.

Testing

DIY test kits: Short-term test (2-7 days): $10-$30 (includes lab analysis). Good for initial screening. Place in the lowest livable level of the home. Long-term test (90+ days): $20-$40. More accurate (radon levels fluctuate seasonally). Alpha-track or electret detectors.

Professional testing: Cost: $100-$300. Uses continuous radon monitor (CRM). Results in 48 hours. Required for real estate transactions in many areas. More accurate than DIY short-term tests.

When to test: Every home should be tested (regardless of age, location, or construction). When buying a home (part of inspection). After mitigation (to verify system is working). Every 2 years (levels can change over time). After major renovations (especially foundation work).

Where radon is highest: Varies by geography. EPA Zone 1 (highest risk): much of the northern US, Appalachian region, Rocky Mountain states. But ANY home in ANY state can have elevated radon.

Mitigation

Sub-slab depressurization (most common): How it works: a pipe is installed through the foundation slab into the gravel beneath. A fan pulls radon-laden air from under the slab and exhausts it above the roofline. Prevents radon from entering the home. Effectiveness: reduces radon by 80-99%. Cost: $800-$2,500 (average: $1,200-$1,500).

Other methods: Sub-membrane depressurization (for crawl spaces): $800-$2,500. Sealing cracks and openings: supplementary measure, not sufficient alone. Heat recovery ventilator (HRV): $1,500-$3,000. Increases ventilation to dilute radon.

Mitigation system components: PVC pipe (3-4 inch, from sub-slab to above roofline). Radon fan ($100-$300, lasts 5-10+ years). Manometer (U-tube gauge, shows system is working). Electrical connection for the fan.

After mitigation: Retest within 24 hours to 30 days. Maintain system (check manometer regularly, replace fan when needed). Running cost: $50-$100/year in electricity. System lasts 20+ years (fans last 5-10+ years).