Radon Removal: What Homeowners Need to Know
Radon is a colorless, odorless radioactive gas that seeps up from the soil into homes, and along Colorado’s Front Range it is a near-universal concern. Radon removal — more precisely, radon mitigation — is the process of lowering indoor radon to safe levels by intercepting the gas and venting it harmlessly outdoors. The term “removal” is slightly misleading: you do not scrub radon out of the air so much as prevent it from accumulating. This guide summarizes EPA and Colorado state guidance current as of 2026 and is informational only — for testing and mitigation decisions, use a certified professional, and consult your physician about health concerns. Below is how radon removal works, what it costs, and why Colorado homes so often need it.
How radon removal actually works
Radon removal is achieved through a mitigation system that captures radon before it enters the living space and routes it outside. The most common and effective approach is active soil depressurization (ASD): a pipe is run from beneath the foundation slab up through the home and out above the roofline, with an inline fan creating suction that draws radon-laden soil gas out before it can seep indoors.
Because radon enters through the soil-to-home pathway — cracks, sumps, slab penetrations — the system works by reversing the pressure that pulls gas inward. The EPA identifies soil depressurization as the most reliable method for most homes. For the full mechanics, the radon testing guide explains how Colorado homes draw soil gas in the first place, and the installation guide walks through the build.
Why Colorado homes so often need radon removal
Colorado’s geology produces high indoor radon. The state’s soils are rich in uranium, which decays into radium and then radon, and the gas migrates up into homes through the foundation. The Colorado Department of Public Health and Environment reports that roughly half of Colorado homes test above the EPA action level of 4.0 picocuries per liter (pCi/L).
The Front Range — Denver, Boulder, Colorado Springs, and the surrounding counties — sits squarely in this high-radon zone. Climate compounds the issue: cold winters mean homes are sealed and heated, and the “stack effect” of warm air rising creates negative pressure at the foundation that actively pulls soil gas inside. The effects of radon guide covers why this matters for long-term health, and the basement radon guide explains why lower levels of a home read highest.
Can you remove radon without a full system?
Homeowners often ask whether simpler measures can lower radon without installing a mitigation system. Some steps help at the margins, but for elevated readings, a proper system is the only reliable solution.
Increasing ventilation — opening windows, running exhaust fans, or adding a heat-recovery ventilator — dilutes indoor radon and can produce a modest reduction. The drawback is that it works only while running, fights against Colorado’s heating-dominated climate, and rarely brings a high reading below the action level on its own. Sealing foundation cracks, sump openings, and slab penetrations reduces entry points and is worthwhile, but sealing alone seldom achieves a sufficient reduction; its main value is improving the performance of an active system.
For readings near the action level, these measures might nudge levels down, but for genuinely elevated radon, active soil depressurization is the proven fix. The EPA is clear that ventilation and sealing are supplements, not substitutes, for a mitigation system when readings warrant action. The reliable path is to test, and if the number is high, install a system rather than relying on partial measures, as the how to get rid of radon guide details.
Testing before removal: you can’t fix what you don’t measure
Radon removal starts with testing, because radon is invisible and odorless. A short-term test (two to seven days) gives a quick screening, while a long-term test (90 days or more) better reflects year-round average exposure. Continuous radon monitors offer ongoing readings.
If a test returns 4.0 pCi/L or higher, the EPA recommends mitigation. Readings between 2.0 and 4.0 pCi/L fall in a zone where the agency suggests considering mitigation, since no level of radon is risk-free. Because Front Range homes so often test high, many buyers and owners test proactively rather than waiting. After any mitigation system is installed, a follow-up test confirms it lowered levels effectively. The radon test kit guide explains the mail-in option, and the digital radon detector guide covers continuous monitors.
Why radon removal matters for health
The reason to remove radon is not abstract. The EPA identifies radon as the leading cause of lung cancer among people who have never smoked and the second leading cause overall, behind smoking. The risk is dose-dependent: the higher the concentration and the longer the exposure, the greater the lifetime risk.
Radon harms through its decay products. As radon breaks down, it produces tiny radioactive particles that attach to dust and are inhaled, lodging in lung tissue where their radiation damages cells over time. There are no acute symptoms — no cough, no irritation, no warning — which is why exposure can continue for years unnoticed. The danger is purely long-term and statistical.
For smokers, the risk compounds dramatically, because radon and tobacco smoke act together to raise lung-cancer risk far beyond either alone. This combined effect makes radon removal especially important in households with smokers, though the EPA recommends mitigation for any home above the action level regardless of smoking status. The long-term health pathway is detailed in the effects of radon guide.
What radon removal costs
A professionally installed active soil depressurization system on the Front Range typically costs $800 to $2,500, with most homes landing in the $1,200 to $1,800 range. The variation depends on several factors.
- Foundation type. A simple slab or basement is cheaper to mitigate than a home with multiple foundation types, crawlspaces, or additions.
- System routing. Running the vent pipe discreetly and reaching above the roofline affects labor and materials.
- Fan and finish. Higher-suction fans and aesthetic routing through interior chases add cost.
- Sealing work. Sealing cracks, sumps, and slab penetrations improves system performance and may add to the bid.
Ongoing costs are modest: the fan runs continuously and adds a few dollars a month to the electric bill, plus minor fan replacement every five to ten years. The full pricing breakdown appears in the cost of radon mitigation guide.
What to expect living with a radon system
Once installed, a radon mitigation system asks little of the homeowner, but knowing what is normal helps you spot the rare problem early.
The fan runs continuously and is designed to do so — it is not switched on and off. Most fans are quiet enough to fade into background noise, especially when mounted in the attic or outside. A slight hum near the fan is normal; a sudden change in sound can signal a failing fan worth checking. The system monitor, usually a simple U-shaped manometer on the vent pipe, shows the fan is creating suction: an even column of liquid means the system is working, while a level column on both sides means the fan has stopped.
Maintenance is minimal. Glance at the manometer periodically, keep the exterior vent clear of obstructions, and plan for fan replacement every five to ten years. After any major change to the home — a basement finish, foundation work, or HVAC alteration — retest, since these can affect radon entry and system performance. Beyond that, the system is a quiet, set-and-forget safeguard. The component details appear in the radon mitigation fan guide.
The radon removal process step by step
A typical professional installation follows a clear sequence and usually takes a single day.
First, the contractor evaluates the foundation and identifies the best suction point, often the sump pit or a hole cored through the slab. They then run PVC piping from that point up through the home or along the exterior to above the roofline. An inline fan is installed, typically in the attic or outside, to create continuous suction.
The contractor seals major foundation openings to improve performance and installs a system monitor — usually a simple manometer — that lets the homeowner verify the fan is working. After installation, a post-mitigation radon test confirms levels have dropped below the action threshold. The mitigation installation guide details each stage.
Radon removal methods beyond soil depressurization
Active soil depressurization is the workhorse, but it is not the only approach, and the best method depends on the home’s construction.
Sub-slab depressurization
The most common form of ASD, used in homes with a concrete slab or basement floor. A suction point is created in the slab, and the fan draws soil gas from beneath it. This is the default for most Front Range homes.
Sub-membrane depressurization
For homes with crawlspaces, a heavy plastic membrane is sealed over the exposed soil, and the fan draws gas from beneath it. This both reduces radon and controls crawlspace moisture, a useful side benefit.
Drain-tile or sump-pit depressurization
Homes with perimeter drain tile or a sump pit can use those existing pathways as the suction point, often simplifying installation.
Passive systems and sealing
Some newer homes are built with passive radon-resistant features — piping that vents soil gas by natural convection without a fan. Sealing foundation cracks alone rarely lowers radon enough on its own but improves the performance of an active system. Where a passive system tests too high, adding a fan converts it to active. The mitigation-fan component is detailed in the radon mitigation fan guide, and the broader options in the radon in homes overview.
What happens if radon stays high after mitigation
A properly designed system almost always brings levels below the action threshold, but occasionally a post-mitigation test still reads high. Knowing why prevents panic and points to the fix.
The usual causes are a fan undersized for the home’s soil, an unsealed secondary suction pathway, multiple foundation types that need more than one suction point, or unsealed openings that let the system “short-circuit” by pulling indoor air instead of soil gas. A certified installer diagnoses these by checking system suction with a manometer and inspecting for leaks.
The remedies are usually straightforward: a higher-suction fan, additional sealing, or a second suction point in a separately pressurized zone. This is one of the strongest arguments for hiring a certified professional who warranties a guaranteed post-mitigation level — they own the problem and the fix if the first design falls short. The diagnostic process is covered in the how to get rid of radon guide.
DIY versus professional radon removal
Mitigation kits exist, and a handy homeowner can install a basic system. But there are real reasons most Colorado homeowners hire a certified professional. Proper system design requires understanding suction-point placement, fan sizing, and venting clearances, and a poorly designed system can fail to reduce radon or even worsen distribution.
Professionals are certified through programs like the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB), follow established standards, and verify results with post-installation testing. They also handle the venting code requirements that keep the exhaust clear of windows and intakes. The trade-offs are weighed in the DIY radon mitigation guide. For a home where the goal is verified, lasting radon reduction, professional installation is the dependable route.
References
- Consumer’s Guide to Radon Reduction — U.S. Environmental Protection Agency
- Radon Program — Colorado Department of Public Health and Environment
- Radon and Lung Health — American Lung Association
Front Range homeowners who want help testing for radon or connecting with a certified mitigation professional can reach out through our contact page.