Radon is a serious health hazard, but many homebuyers discover after closing that it wasn't part of their inspection. Whether radon testing gets included depends entirely on the inspector you hire and the inspection package you choose. Understanding what's standard—and what costs extra—saves you money and protects your family.
Standard Home Inspection vs. Radon Testing
Most general home inspections do not automatically include radon testing. A typical inspection covers the structure, roof, foundation, electrical systems, plumbing, HVAC, and visible interior components. Radon detection requires specialized equipment and a separate protocol that takes 48 hours to several days to complete properly.
When you hire an inspector, confirm what's bundled. Some inspectors offer radon as an add-on for $150–$300. Others partner with labs or specialize in radon and include it in premium packages starting around $400–$600 for the full inspection. Ask directly before booking.
Why Radon Isn't Always Included
Radon testing requires EPA-approved continuous radon monitors or charcoal canisters left in the home's lowest livable level. Results take time. A standard four-hour inspection can't accommodate this—it's a separate engagement that needs scheduling flexibility and a follow-up visit to retrieve equipment.
Additionally, not all inspectors are trained or certified in radon measurement. Some states require specific credentials. If your inspector isn't equipped to do it, they'll refer you to a radon specialist, which means another service call and fee.
When to Request Radon Testing
During your home purchase: If you're buying in a high-radon zone (check your county's EPA map), request radon testing in your inspection contingency. Real estate agents and sellers often budget for this, especially in Midwest and Northeast markets where radon is common.
As a separate follow-up: Schedule radon testing immediately after your general inspection if it wasn't included. Don't wait until after closing—you'll have no recourse if elevated levels are found.
For rental or existing-home decisions: If you're already in a home, test every 2 years or after any foundation work. Radon levels fluctuate seasonally.
What to Expect: Timeline and Cost
| Service | Typical Cost | Timeline | |---------|-------------|----------| | Radon testing only (short-term) | $150–$250 | 48 hours to 1 week | | Radon testing + general inspection bundle | $400–$600 | 4 hours inspection + 48 hours radon | | Radon remediation (if needed) | $1,200–$2,500 | 2–5 days installation |
Short-term tests (2–7 days) are standard during home purchase. Long-term tests take 3–12 months and give a better seasonal average but aren't practical for transactions.
Key Questions to Ask Your Inspector
- "Is radon testing included in your standard inspection?" Get a clear yes or no.
- "Are you EPA-certified or trained in radon measurement?" Ensures proper protocol.
- "What does the radon report include?" You need picocuries per liter (pCi/L) readings. The EPA action level is 4 pCi/L or above.
- "If levels are high, do you have remediation recommendations?" Some inspectors partner with mitigation contractors.
- "How do you handle radon in high-risk areas?" Experienced inspectors in radon-prone regions may make it standard.
Interpreting Radon Results
Results below 2 pCi/L are considered safe. Between 2–4 pCi/L, the EPA recommends testing again or considering mitigation. Above 4 pCi/L, radon remediation is strongly advised—a sub-slab depressurization system typically costs $1,200–$2,500 and reduces levels by 50–99%.
Don't panic at elevated numbers, but act quickly. Radon is fixable, and most sellers will negotiate credits or remediation before closing if it's disclosed during inspection.
Finding a Qualified Inspector with Radon Services
If you need both general inspection and radon testing, using Mercoly lets you compare and find trusted home inspection providers in one place, so you can see upfront which ones offer radon as standard or add-on services. Filter by your location and service offerings to avoid multiple quotes and phone calls.
Frequently Asked Questions
Q: Can I negotiate radon remediation costs into the home price if testing reveals high levels? Yes—most sellers will either credit you toward remediation, hire a contractor themselves, or reduce the offer price. Document the inspection report and include radon remediation costs in your negotiation.
Q: Is radon testing required by law? No, but it's required by your lender in some high-risk states and recommended by the EPA nationwide. Check local disclosure laws; some states require sellers to disclose known radon issues.
Q: How accurate are DIY radon test kits from hardware stores? They're cheaper ($10–$30) but less reliable than professional-grade equipment. For a real estate transaction, invest in certified testing—inspectors use calibrated monitors that hold up in disputes.
Ready to find an inspector who covers radon testing and all the essentials? Start comparing qualified providers today.