Quick Answer
A radon mitigation system costs $800 to $2,500, averaging around $1,200 for a standard active soil depressurization system.
Passive systems installed during new construction cost less, typically $300 to $1,500, since they're integrated into the build rather than retrofitted. More complex situations — crawl space encapsulation combined with mitigation, or water-based radon — can run $3,000 to $5,000.
Radon enters homes regardless of age or construction quality, through foundation cracks, gaps, and soil contact — meaning even a newly built home isn't automatically protected without a proper mitigation system in place.
Radon Mitigation Cost by System Type
Pricing varies based on system type, foundation type, and whether you're building new or retrofitting.
| System Type | Typical Cost | Notes |
|---|---|---|
| Passive system (new construction) | $300 – $1,500 | Relies on natural pressure differentials rather than a fan. Required by code in some states (including Illinois) for new construction. |
| Active soil depressurization (most common) | $800 – $2,500 | The standard, most effective system — a pipe and fan actively pull radon from beneath the foundation and vent it safely above the roofline. |
| Crawl space radon system | $1,000 – $3,000 | Requires vapor barrier encapsulation of the crawl space combined with a depressurization system. |
| Water-based radon mitigation | $1,200 – $5,000 | Addresses radon entering through well water, separate from soil-based radon entering through the foundation. |
| Professional radon test | $125 – $400 | Includes the testing device, technician setup and pickup, and lab analysis fees. |
| Permit (where required) | $25 – $150 | Most mitigation contractors include this fee in their overall estimate. |
Check Your Local Requirements
Some states require radon-resistant construction by code
Confirm whether your jurisdiction requires a passive or active radon system before you finalize your build.
Why Radon Mitigation Matters More Than the Price Tag Suggests
Five reasons this is a health and safety investment, not just a building code checkbox.
According to the EPA, radon exposure is the second leading cause of lung cancer overall and the number one cause among people who have never smoked — a serious, well-documented health risk, not a minor home maintenance issue.
Radon cannot be seen, smelled, or tasted. A test is the only way to know whether levels in a specific home are elevated, regardless of how old or new the house is.
Radon risk varies by region and even by individual property, but the EPA estimates this affects a meaningful share of homes nationwide — testing is recommended regardless of geographic radon zone.
Radon enters through foundation cracks, gaps, and soil contact regardless of how new or well-built a home is. A newly constructed home with no mitigation system can have the same elevated radon risk as an older one.
Radon testing and mitigation frequently come up during real estate transactions, and unresolved radon issues can complicate a sale or reduce buyer interest, even when the seller is not legally required to address it.
It's Far Cheaper to Build It In Than Retrofit It Later
Installing a passive radon-resistant system during new construction — vent piping, sealed sump covers, and a vapor barrier under the slab — costs significantly less than retrofitting an active system into a completed home. If the passive system doesn't bring levels below the EPA action threshold, a fan can be added later relatively easily since the piping is already in place.
If you're finalizing your house plan now, this is worth discussing with your builder before the foundation is poured, not after.
Planning your foundation budget?
See how radon-resistant construction fits into your overall build cost.
Get Cost Report →Have a crawl space?
Radon mitigation in crawl spaces often pairs with encapsulation — see the combined cost.
See Encapsulation Cost →Crawl Spaces Often Need Both Encapsulation and Mitigation
If your home has a crawl space rather than a slab or basement, radon mitigation typically needs to be paired with vapor barrier encapsulation to be effective — sealing the crawl space and managing radon are closely related projects that are often bid and installed together.
Understanding both costs together gives you a more accurate total budget if your build includes a crawl space foundation.
Recommended Tools and Reports
Permit Report
Check whether your jurisdiction requires radon-resistant construction by code.
Check Permits →Cost Report
Get a full build cost estimate including foundation and indoor air quality features.
Get Cost Report →Is My Foundation Bid Too High?
Confirm radon-resistant features are included in your foundation contractor's bid.
Check Foundation Bid →Crawl Space Encapsulation Cost
See how crawl space encapsulation and radon mitigation often combine.
See Encapsulation Cost →Frequently Asked Questions
How much does a radon mitigation system cost?
A radon mitigation system typically costs $800 to $2,500 to install, with a national average around $1,200. Passive systems installed during new construction run lower, around $300 to $1,500, while crawl space or water-based systems can run higher, up to $3,000 to $5,000.
Is radon mitigation required for new construction?
Requirements vary by state and jurisdiction. Some states, including Illinois, require a passive radon-resistant system to be installed in all new construction by code. Many other areas recommend but do not legally require it. Check your local building code or ask your permit office directly.
How do I know if my home has a radon problem?
A radon test is the only way to know. Professional testing costs $125 to $400 and typically measures radon over a 48-hour period. DIY test kits are available for $10 to $30 and are reasonably reliable for an initial screening, though professional testing is generally recommended for real estate transactions.
What is the EPA action level for radon?
The EPA recommends taking action to reduce radon levels when results reach 4.0 picocuries per liter (pCi/L) or higher. However, the EPA notes there is no known safe level of radon exposure, so some homeowners choose to mitigate at lower levels as well.
Does homeowners insurance cover radon mitigation?
No. Standard homeowners insurance policies do not cover radon testing or mitigation, since it is considered an ongoing maintenance and environmental issue rather than sudden accidental damage. Most standard home warranties also exclude radon mitigation.
How much does it cost to run a radon mitigation system?
Most active radon fans use about the same electricity as a 60-watt light bulb, adding roughly $70 to $300 per year to electric bills depending on the fan size and local energy costs. In colder climates, the cost of replacing exhausted conditioned air can add further to ongoing operating costs.
Before You Finalize Your Foundation
Check Whether Radon-Resistant Construction Applies to You
Building it in during construction is far more cost-effective than retrofitting it later.