How to Remove Radon From Home: A Plain Guide
Radon is a colorless, odorless radioactive gas that seeps up from soil and collects inside homes, and it is the second leading cause of lung cancer in the United States after smoking. Colorado sits in a high-radon region, and much of the Front Range, from Denver to Colorado Springs, shows elevated potential, which makes the question of how to remove radon from home especially relevant for local owners. The good news is that radon is fixable with established engineering methods. This guide summarizes EPA and Colorado Department of Public Health and Environment guidance current as of 2026; it is educational and not a substitute for a certified radon professional or medical advice from your physician.
How Do You Remove Radon From a Home?
You cannot remove radon the way you remove a stain; you reduce its concentration to a safe level through mitigation. The most common and effective method is active soil depressurization, which uses a fan and a vent pipe to draw radon from beneath the foundation and exhaust it above the roofline before it enters the living space. Done correctly, this approach routinely brings high radon levels down to a fraction of their original reading.
Mitigation always follows testing, never the other way around. You first confirm the radon level, then design a system sized to the home and its foundation type. Front Range homeowners can learn how testing works through the broader hub on radon testing in Colorado before arranging any mitigation work.
What Radon Level Requires Action?
The EPA recommends taking action to mitigate when a home’s radon level reaches or exceeds 4.0 picocuries per liter, expressed as pCi/L. The agency also notes that there is no completely safe level, and that homeowners may consider mitigation between 2.0 and 4.0 pCi/L as well, since risk continues below the action threshold. Radon levels are measured in air, and the unit reflects radioactive decay.
Because radon enters from the soil, levels are typically highest in basements and lowest on upper floors. Colorado’s geology drives many Front Range homes above the action level, which is why the state health department encourages every household to test. A reading at or above 4.0 pCi/L is a clear signal to mitigate, and the resource on what level of radon is dangerous explains the risk gradient in more depth.
Active Soil Depressurization: The Gold Standard
Active soil depressurization, sometimes called sub-slab depressurization, is the method the EPA identifies as the most reliable for most homes. A pipe is inserted through the slab or into a sump or drain tile, and an inline fan continuously draws soil gas up through the pipe and discharges it above the roof. The fan creates a low-pressure zone beneath the slab so radon flows into the pipe rather than into the home.
The system runs quietly and continuously, using modest electricity. A properly installed system includes a monitor, often a simple U-tube manometer, that shows the fan is working. The vent pipe terminates above the roofline and away from windows to prevent re-entry. This is the workhorse of radon mitigation and the design most Front Range contractors will recommend.
Sealing and Other Supporting Measures
Sealing cracks and openings in the foundation supports a depressurization system by reducing the paths radon uses to enter and the air the fan must move. On its own, sealing rarely lowers radon enough to meet the action level, so the EPA treats it as a complement rather than a standalone fix. Covering a sump, sealing a slab crack, and closing gaps around pipe penetrations all help the active system perform efficiently.
Other Mitigation Approaches
Beyond sub-slab depressurization, a few alternatives fit specific situations. Homes with crawlspaces may use sub-membrane depressurization, which places a sealed plastic membrane over the soil and draws radon from beneath it. Drain-tile or sump-pit suction taps into existing drainage systems. Increasing ventilation can reduce radon modestly but is rarely sufficient alone and can raise heating costs in Colorado winters.
The right method depends on foundation type, soil conditions, and the home’s layout. A certified mitigator evaluates these factors and selects the system most likely to bring the level below the action threshold reliably. The overview of how radon mitigation works compares the approaches in detail for homeowners weighing options.
What Does Radon Mitigation Cost?
Mitigation cost depends on the home’s size, foundation type, and the complexity of the installation. Industry estimates commonly place a typical residential active soil depressurization system in a range of several hundred to a couple of thousand dollars installed, with complex multi-foundation homes costing more. Ongoing costs are limited to modest fan electricity and occasional fan replacement over the system’s life.
That figure is small relative to the lung-cancer risk it addresses, and many Front Range buyers and sellers fold mitigation into a transaction. A system also lowers radon for the life of the home, not just for one occupant. Homeowners can review regional pricing context through the guide on the average cost of a radon mitigation system.
Should You DIY or Hire a Professional?
Radon mitigation is a job most homeowners should leave to a certified professional. Designing a system that reliably depressurizes the sub-slab, routing the vent correctly, and confirming the result with post-mitigation testing all require training. A poorly designed system can fail to lower radon or, worse, give false confidence. Many states, and many lenders in real estate deals, expect a certified installer.
Certification programs through national radon proficiency bodies indicate an installer has met training and competency standards. After installation, a follow-up radon test verifies the system brought levels below the action threshold. The state health department recommends retesting after any mitigation and periodically thereafter, since fans wear out and home conditions change. Skipping the verification test defeats the purpose of the work.
Why Colorado’s Front Range Is a High-Radon Region
Radon forms from the natural radioactive decay of uranium in soil and rock, and the geology beneath the Front Range is rich in the uranium-bearing minerals that produce it. Much of Colorado falls into the EPA’s highest radon-potential zone, and the state health department reports that a large share of homes tested across the region show levels at or above the action threshold. New and old homes alike are affected, because the gas enters through whatever soil-contact openings a foundation provides.
Colorado’s climate amplifies the issue through the stack effect. In cold months, warm indoor air rises and escapes upper levels, creating a slight negative pressure at the foundation that actively draws soil gas, and radon with it, into the home. This is why winter readings often run higher than summer ones along the Front Range. The combination of uranium-rich soil and seasonal pressure differences makes testing every home a sensible default rather than an optional precaution in this part of the state.
Radon Entry Points: How the Gas Gets In
Understanding where radon enters clarifies why mitigation targets the soil beneath the slab. The gas migrates through any opening between the home and the ground: cracks in the slab or foundation walls, gaps around pipe and utility penetrations, sump pits, floor drains, and the porous block of a foundation wall. Even a tightly built home has enough of these pathways for radon to accumulate when indoor pressure favors it.
Because the gas comes from below, the lowest occupied level almost always shows the highest concentration, which is why testing and mitigation focus there. Sealing visible cracks reduces entry but rarely solves the problem alone, since invisible pathways remain. Active soil depressurization works precisely because it reverses the pressure relationship, drawing soil gas into a vent pipe before it can find any of these entry points. The detail of how the gas migrates is explored in the resource on how radon gets into homes.
What Mitigation Does Not Fix
Setting expectations correctly matters, because a mitigation system addresses radon and only radon. It will not resolve general moisture problems, mold, or poor indoor air quality from other sources, even though those issues sometimes coexist with radon entry through the same foundation pathways. A homeowner who installs a radon system expecting it to dry out a damp basement will be disappointed; those are separate problems requiring separate solutions.
A mitigation system also depends on continued operation. If the fan loses power or fails, radon levels can climb back toward their original readings, which is why the system is designed to run continuously and why monitoring and periodic retesting matter. The system reduces radon while it works, but it is not a permanent one-and-done modification that needs no attention. Understanding these limits helps a homeowner treat mitigation as one targeted intervention within a broader approach to a healthy home, rather than a cure-all for every basement concern.
After Mitigation: Verify and Maintain
Installing a system is not the finish line; confirming it worked is. Run a post-mitigation radon test, ideally a few weeks after installation, to verify the level fell below 4.0 pCi/L. Keep the fan running continuously, and check the system monitor periodically to confirm the fan is operating. A manometer reading that drops to level can signal a failed fan.
Radon fans typically last several years before needing replacement, and the EPA recommends retesting every couple of years even with a working system. Colorado’s seasonal swings, especially the winter stack effect that pulls soil gas indoors, make periodic verification worthwhile for Front Range homes. A maintained system is a permanent reduction in a serious health risk.
The Health Stakes Behind Radon Reduction
The reason mitigation is worth the cost lies in the disease it prevents. Radon is the leading cause of lung cancer among people who have never smoked and the second leading cause overall, according to the EPA and the American Lung Association. The gas decays into radioactive particles that lodge in lung tissue, and over years of exposure that radiation can damage cells and lead to cancer. The risk is cumulative, so the longer a household lives with elevated radon, the greater the danger.
The risk also compounds with smoking. A smoker in a high-radon home faces a substantially higher lung-cancer risk than either factor alone would produce. Because the gas is invisible and odorless and the disease takes years to develop, the hazard is easy to ignore until it is too late. That latency is precisely why authorities urge testing and prompt mitigation rather than waiting for symptoms, which by definition appear only after damage is done. Reducing radon is one of the few lung-cancer risk factors a homeowner can eliminate with a one-time engineering fix.
Comparing Mitigation Methods by Foundation Type
The right system follows from the home’s construction. A poured-slab or basement home is the textbook case for sub-slab depressurization, where a pipe through the slab and an inline fan handle the job efficiently. A home with a crawlspace usually calls for sub-membrane depressurization, sealing a plastic membrane over the soil and drawing radon from beneath it, which adds material and labor.
Homes with mixed foundations, common across the Front Range where additions and remodels join different construction types, may need a combined approach with more than one suction point. A home built over a sump pit or perimeter drain tile can sometimes use that existing feature as the suction point, simplifying the work. A certified mitigator evaluates the foundation, the soil, and the home’s layout to select the design most likely to bring levels below the action threshold reliably. Matching the method to the foundation is what separates a system that works the first time from one that requires costly rework, and it is a key reason professional installation outperforms guesswork.
References
- Consumer’s Guide to Radon Reduction — U.S. Environmental Protection Agency
- Radon Program and Guidance — Colorado Department of Public Health and Environment
- Radon and Lung Health — American Lung Association
If you own or are buying a home along the Front Range and want a vetted, independent professional to test radon levels or evaluate a mitigation plan, reach out through our contact page and we will help connect you with a qualified local specialist.