How to Get Rid of Radon: A Plain-Language Guide
Once a home tests at or above the EPA’s action level of 4 picocuries per liter (pCi/L), the question shifts from whether radon is present to how to get rid of it. The good news is that radon reduction is a well-established field with proven methods that reliably lower indoor levels, often dramatically. The right approach depends on the home’s foundation, but for most houses one technique does the heavy lifting. This guide explains how to get rid of radon, what each method does, what it costs along the Front Range, and where do-it-yourself effort ends and professional work begins. This guide summarizes EPA and Colorado state guidance current as of 2026 and is educational only; consult a certified mitigation professional for your home.
How to get rid of radon: the short answer
The most effective and common way to get rid of radon is active sub-slab depressurization. A contractor installs a vent pipe through the foundation slab and connects it to a continuously running inline fan that draws radon-laden soil gas from beneath the home and exhausts it above the roofline, before it can enter living space. Properly designed, this method routinely reduces indoor radon to well below 4 pCi/L, often to 1 to 2 pCi/L or lower.
Sealing cracks and openings helps the system work efficiently but does not, on its own, solve a radon problem. Ventilation changes can lower levels modestly but are rarely sufficient where readings are significantly elevated. For Colorado homes, where high readings are common, active mitigation is usually the durable answer. The full overview is in the radon testing guide, and the mitigation process is detailed in the radon remediation guide.
Before mitigating, confirm the elevated reading. Because radon fluctuates, a single short-term result is typically verified with a follow-up test so the home is not mitigated on the basis of an outlier.
Sub-slab depressurization explained
This method works by reversing the pressure that pulls soil gas into the house. The fan creates a slight vacuum beneath the slab, so radon is captured under the foundation and routed up and out rather than seeping through cracks. For homes with a basement or slab-on-grade foundation, a suction point is cut through the slab, the pipe is routed up through the house or along the exterior, and the fan is mounted in an attic or outside, never in living space.
The specifics of how the fan and piping are sized and placed are covered in the radon mitigation fan guide and the installing a radon mitigation system guide. A post-installation test confirms the system actually achieved the target reduction.
Crawl spaces and other foundations
Homes with crawl spaces use a variation called sub-membrane depressurization, where a sealed plastic membrane is laid over the crawl space soil and a fan draws gas from beneath it. Homes with multiple foundation types, additions, or sumps may need more than one suction point. These complications are part of why a professional assessment matters, since the foundation determines the design.
A sump pit, common in Front Range basements, can be incorporated into the system by sealing it with an airtight lid and drawing suction from it, which serves double duty for water management and radon. Homes built over a combination of slab and crawl space, or with an addition on a different foundation, often cannot be solved by a single suction point because air will not travel freely under the entire footprint. A pre-installation diagnostic, sometimes including a pressure-field extension test, tells the installer how many suction points the home actually needs.
Sealing and ventilation: helpers, not solutions
Sealing foundation cracks, sump covers, and pipe penetrations reduces the entry points and improves the efficiency of an active system, but the EPA notes that sealing alone has not reliably or permanently lowered radon. Soil gas finds new paths over time as a house settles. Treat sealing as a supporting measure paired with depressurization, not a substitute.
Increasing ventilation, such as running a heat-recovery ventilator, can dilute indoor radon and may help in some homes, but it raises energy costs and is generally less effective than depressurization for significantly elevated levels. For a quick orientation to the range of approaches, the radon remediation guide compares them.
A heat-recovery ventilator can be a reasonable supplement in tightly sealed homes where some controlled fresh-air exchange is desirable anyway, recovering much of the heat from outgoing air to limit the energy penalty. But for a home reading well above the action level, relying on ventilation alone usually leaves levels higher than active depressurization would achieve. The hierarchy is consistent: depressurization does the heavy lifting, sealing supports it, and ventilation plays a secondary role.
What radon reduction costs in Colorado
A professionally installed active radon mitigation system typically runs in the range of roughly $800 to $2,500 along the Front Range, with most homes landing in the middle of that band. Price varies with foundation type, the number of suction points needed, the routing of the pipe, and finish considerations. Homes needing multiple suction points or sub-membrane systems for crawl spaces sit toward the higher end.
Ongoing cost is modest: the fan runs continuously and uses a small amount of electricity, and fans are typically replaced every several years. A detailed cost breakdown is available in the radon remediation cost guide. Against the lung-cancer risk radon poses, mitigation is widely regarded as a high-value investment.
DIY versus hiring a professional
Some homeowners install systems themselves, and materials are available, but doing it well requires correctly diagnosing the foundation, sizing the fan, placing the suction point, sealing the slab, routing the exhaust to code, and verifying the result with a post-test. Mistakes can leave levels elevated or vent gas improperly. The realities of the do-it-yourself route are laid out in the DIY radon mitigation guide.
For most homeowners, a certified radon mitigation professional is the safer choice, particularly because Colorado now has contractor certification requirements and because a guaranteed post-mitigation test confirms the home is safe. When a reading is elevated, consulting a professional ensures the system actually gets rid of the radon rather than appearing to.
Confirming the radon is actually gone
Installing a system is only half the job; verifying the result completes it. A post-mitigation test, conducted after the system has run long enough to stabilize the home, confirms the level dropped below 4 pCi/L. Reputable professionals include this test and stand behind a target reading, adjusting the system, adding a suction point, or upsizing the fan if the first attempt falls short. A homeowner should never consider a project finished until a post-test documents success.
Long-term verification matters too. A simple system manometer, a U-shaped gauge on the vent pipe, shows at a glance whether the fan is still pulling suction; a change in the fluid levels signals a problem. Periodic retesting, every couple of years and after any major foundation or HVAC work, confirms the reduction has held. Getting rid of radon is durable when the system is well designed, but it depends on a running fan, which makes occasional verification a small but worthwhile habit.
What to expect during installation
A typical residential radon mitigation install is completed in a day for a straightforward home. The crew identifies the suction point, cores a hole through the slab, and excavates a small pit beneath to create a plenum for the fan to draw from. They route PVC pipe from that point up through the home’s interior or along an exterior wall to a fan mounted in the attic or outside, then continue the exhaust above the roofline away from windows and air intakes.
The crew seals the slab penetration and any obvious openings, such as a sump pit lid or visible cracks, to help the system maintain suction. A manometer is installed on the pipe so the homeowner can see at a glance that the fan is pulling. After the system runs long enough to stabilize the home, a post-mitigation test confirms the level has dropped below the action threshold. Homeowners should expect some noise from the fan and airflow, which a well-designed system keeps to a low hum.
Maintaining the system over time
Getting rid of radon is durable, but the system needs minimal ongoing attention to stay effective. The fan runs continuously and should never be switched off, since levels rebound within days if it stops. Homeowners should periodically glance at the manometer; a change in the fluid levels signals reduced suction, often from a failing fan or a blockage. The fan itself is a wear item, typically lasting several years before it needs replacement.
Beyond the fan, retesting every couple of years and after any major foundation or HVAC work confirms the reduction has held. Renovations that alter the foundation, the addition of a new wing, or significant changes to heating and ventilation can shift radon dynamics, warranting a fresh test. These habits are light, but they ensure the investment keeps doing its job. For Front Range homeowners who want certainty that a system is sized and performing correctly, a certified mitigation professional can verify the design and the post-mitigation result.
Why some homes need more than one approach
A minority of homes resist a single-method fix and need a combined strategy. A large or rambling footprint, a home built in stages over different foundations, or unusually tight sub-slab soil can prevent one suction point from depressurizing the whole area. In these cases an installer may add suction points, upsize the fan, or pair depressurization with improved sealing and supplemental ventilation to reach the target reduction.
This is why a post-mitigation test is non-negotiable: it reveals whether the chosen approach actually worked or whether the system needs adjustment. A reputable professional treats the first installation as a hypothesis to be verified, not a finished product. If the post-test still shows elevated levels, the fix is to refine the system, add capacity, or address an overlooked entry pathway, until a confirming test shows the home is below 4 pCi/L. Getting rid of radon reliably sometimes takes iteration, and the verification step is what ensures the household ends up actually protected rather than merely reassured.
Getting rid of radon in new construction
For homes being built or recently built, the cheapest time to address radon is during construction. Radon-resistant new construction installs passive features, a gas-permeable layer beneath the slab, a sealed vapor barrier, and a vent pipe routed from below the foundation up through the roof, so the home is ready for a fan if testing later warrants one. Activating such a system, if needed, is far simpler and less expensive than retrofitting a home with no passive groundwork.
Many Front Range jurisdictions now require these passive measures in new homes, but a passive system is not a guarantee. The only way to confirm a new home is below the action level is to test it after occupancy, under closed-house conditions. If the passive system alone does not bring the level down, adding an inline fan converts it to an active system that almost always succeeds. Buyers of new construction should ask whether radon-resistant features are present and, regardless of the answer, test the finished home rather than assuming the builder’s measures were sufficient.
References
- Consumer’s Guide to Radon Reduction — U.S. EPA
- Colorado Radon Mitigation Program — Colorado Department of Public Health and Environment
- Radon Reduction and Lung Health — American Lung Association
Front Range homeowners with an elevated reading who want a certified pro to design and verify a system can connect with a vetted local mitigation specialist here.