A practical guide to DIY radon mitigation: What you can (and can’t) do yourself
TL;DR: If you’ve been monitoring your home for radon for 90 days or more, and levels are consistently reading above 4.0 pCi/L (or 150 Bq/m³), then it’s time to mitigate. There are several DIY steps you can try first, including sealing foundation cracks or increasing ventilation. If you try these and radon levels are still high, then mitigation by a qualified or certified professional is recommended for a safe, lasting, and reliable solution to reduce radon. This usually takes the form of an Active Sub-Slab Depressurization (ASD) system. The cost is typically between $1,200–$2,500 depending on the size and type of your home. Results are typically seen within 24–48 hours. Continue to monitor after mitigation to ensure that the system is working and that your family is safe from radon.
Have you recently tested your home and discovered high radon levels? It’s very normal to feel daunted and a bit panicky. If you’re reading this, then you probably already know that radon is a radioactive gas and that long-term exposure to high radon levels is the leading cause of lung cancer among non-smokers in the United States.
Unsure what radon actually is? Read our in-depth guide first: What is radon? Understanding the invisible gas and safe indoor levels.
Although it’s a daunting issue, high radon inside your home is something that can be fixed, with the results usually permanent. As the EPA (Environmental Protection Agency) states:
Radon reduction systems work. Some radon reduction systems can reduce radon levels in your home by up to 99 percent. Most homes can be fixed for about the same cost as other common home repairs.
Your next thought is likely: How do I fix my radon problem, and can I do it myself?
The short answer is yes, there are several DIY steps you can take to lower your radon exposure which we explore below. However, the EPA strongly advises that if you make some simple fixes and your average radon levels remain consistently at or above 4.0 pCi/L (around 150 Bq/m³ if you’re outside the US) then you likely need a professional mitigation system, usually an Active Sub-Slab Depressurization (ASD) system, installed by a certified or qualified radon mitigation professional.
While it’s possible to install the system yourself with the correct training course or information from your state radon office, we recommend getting help from a pro. Without the proper equipment or technical and building structure knowledge, there’s a chance of actually increasing your radon level. You might accidentally create other hazards or end up increasing costs if something goes wrong.
How do I get started with fixing my radon problem?
Here is a straightforward, step-by-step guide on what DIY radon mitigation looks like, what actually works, and how to ensure your home is (and remains) safe from radon.
Step 1: Confirm your home’s average radon levels with continuous monitoring
Before you spend weekends caulking your basement or hundreds of dollars on supplies, make sure you actually have a long-term radon problem.
Short-term, mail-in charcoal tests likely won’t give you an accurate picture. Radon levels fluctuate constantly, especially when the weather changes (such as snowfall or heavy rainfall). A high reading from a 48-hour test does not necessarily mean your home’s year-round average is dangerous.
Read our guide on radon testing to learn more: How to get started with radon testing in 2026.
The DIY fix: Don’t guess what your radon levels are. Install a continuous digital radon monitor like the Airthings Corentium Home 2 or the View Plus. Let it monitor for at least 30 days in the lowest lived-in level of your home, preferably in the colder months, to establish a true, accurate baseline. If this long-term average remains above 4.0 pCi/L, proceed to the mitigation steps below.
Step 2: Seal radon entry points in your foundation (passive mitigation)
Radon gas is pulled up from the soil underneath and then into your home because the air pressure inside your house is lower than the pressure in the ground. By sealing the gaps in your home’s foundation, you can stop the gas from entering.
While sealing alone rarely fixes a severe radon problem, it is an excellent DIY starting point that can noticeably lower your numbers.
- Caulk foundation cracks: Inspect your basement floor and walls. Clean out any visible cracks and fill them with a high-quality, elastomeric polyurethane caulk (do not use standard silicone, as it will peel away from concrete over time).
- Seal pipe penetrations: Check the areas where plumbing pipes, wiring, or gas lines pass through your concrete floor or walls. Seal these gaps tightly with expanding foam or polyurethane caulk.
- Cover your sump pump: If you have an open sump pit in your basement, it is effectively an open chimney for radon gas. Purchase and install an airtight, gas-tight sump pump cover. Ensure all pipe penetrations through the lid are sealed with rubber grommets.
- Treat exposed earth: If your home has a crawlspace with an exposed dirt floor, lay down a thick, high-density polyethylene vapor barrier (at least 6-mil thick). Overlap the seams and tape them securely to the foundation walls.
Step 3: Improve home ventilation
Radon builds up when a house is sealed tight. By increasing the circulation of fresh outdoor air, you can dilute radon gas concentrations indoors.
- The DIY fix: If you have a basement with windows, try opening the windows on opposite sides of the room to create a cross-breeze, or run a window fan exhausting air out of the house.
- The catch: This is a temporary, climate-dependent solution. It is not energy-efficient during cold US winters or sweltering summers, and you cannot leave your windows open year-round. It is a great stopgap measure to temporarily lower levels while you work on permanent mitigation.
Step 4: When should I call a radon professional (active mitigation)?
If you have already tried sealing foundation cracks, increasing basement ventilation, or treating exposed earth, but your radon monitor still shows levels consistently above 4.0 pCi/L, your DIY efforts have likely reached their limit. You need a system like Active Sub-Slab Depressurization (ASD), which is regarded as the “gold standard” for reducing radon in a home.
How does Active Sub-Slab Depressurization (ASD) work?
ASD works by using a continuously operating fan (often known as a radon fan) to create low pressure beneath a home’s foundation. This helps draw radon gas from the soil and then vents it outside with a fan before it enters the house. As a primary EPA-recognized technique, as described in the EPA’s Consumers’ guide to radon reduction: how to fix your home, ASD involves PVC piping inserted through the slab to establish a suction field, effectively reversing the natural pressure difference that draws radon into the building.
Why this is NOT a DIY job
- Installing an ASD system requires specialized diagnostic pressure testing to ensure the fan is strong enough to pull air from beneath your entire foundation.
- Improperly installing a radon fan can actually reverse your home’s airflow, pulling more radon inside or causing deadly carbon monoxide to backdraft from your furnace.
- Certified contractors guarantee their work and will ensure the system brings your levels below the EPA action limit.
What about HRVs (heat recovery ventilation systems)?
An HRV system, also called an air-to-air heat exchanger, can be installed to offer a permanent way to increase ventilation, which will help reduce the radon levels in your home. These help increase ventilation by introducing outdoor air, then using the heated or cooled air being exhausted to warm or cool the incoming air. HRVs can be designed to ventilate all or part of your home, although they are generally best for reducing radon levels when used to ventilate only the basement. To ensure whole-home radon safety, ASD is generally recommended.
Where to find a certified radon professional
Health authorities, like the EPA, recommend that you use a certified or qualified professional. Websites like the NRPP (National Radon Proficiency Program) in the US have resources guiding you on how to find a certified radon mitigation professional.
For Canada, CNRPP (Canadian National Radon Proficiency Program) has similar guides.
How long does radon mitigation take?
Installing a radon mitigation system typically takes around one day. You can expect to see radon drop to a safe level around 24–48 hours after installation.
How much does professional radon mitigation cost?
Radon mitigation costs will vary according to the size and type of your home, as this might affect the type of system you need. National averages vary, but systems typically cost anywhere between $1,200–$2,500.
The EPA recommends getting an estimate from one or more qualified radon mitigation contractors for a comparison.
Check out our guide, updated as of September 2026, on DIY vs. professional radon mitigation costs.
Step 5: Why you need to keep monitoring after mitigation
Radon mitigation is not a one-off “set it and forget it” solution. Houses settle, new cracks form, and mitigation fans can eventually burn out (usually after 5 to 10 years of use). All these things mean it’s super important to keep monitoring your radon levels continuously after mitigation. If you have a digital monitor, especially one that’s connected to an app like the Airthings Corentium Home 2, you’ll be alerted if your radon levels change or start to creep back up to unsafe levels.
Acting on high radon levels: Airthings case study
For Judith Spence, radon wasn’t something at the top of her mind when she moved from the city to the Canadian countryside for a healthier life. After discovering uranium mining in the region and testing her home with an Airthings monitor, Judith discovered that her home’s radon levels were around 100 times higher than the average level found outdoors. Judith’s husband worked to install a radon mitigation system and seal cracks around the foundations. Once this was up and running, their Airthings monitor showed radon levels dropping almost immediately after installation, helping them regain peace of mind that their home was safe and healthy.
Frequently Asked Questions (FAQ)
Can I mitigate radon myself?
Yes, in some cases. Handy homeowners may be able to seal cracks, improve ventilation, or install a basic fan-assisted mitigation system themselves. However, effective radon reduction often requires specialized knowledge of airflow, pressure, and building design, so professional help may still be recommended for higher levels.
Does opening windows reduce radon?
Yes, temporarily. Opening windows introduces fresh air that dilutes the radon concentration. However, once the windows are closed, radon levels will return to their previous highs within a matter of hours.
How long does DIY radon mitigation take?
Simple fixes like sealing cracks or improving ventilation can often be completed in a weekend. More advanced DIY systems, such as active sub-slab depressurization, may take several days depending on the size and construction of the home.
Will sealing foundation cracks stop radon?
Not completely. Sealing visible cracks and gaps can help reduce some radon entry points, but on its own it is usually not enough to significantly lower radon levels. Sealing is most effective when combined with an active mitigation system.
How much is professional radon mitigation?
In the US, a professionally installed active sub-slab depressurization system typically costs between $1,200 and $2,500, depending on your home’s layout, foundation type, and the local climate.
How do I know if my DIY mitigation worked?
The only reliable way is to test again after making changes. Retesting with a long-term radon monitor or test kit will show whether radon levels have been reduced to a safer range.
Can an air purifier remove radon?
No. Radon is a radioactive gas, not a physical particle. Standard HEPA filters and air purifiers cannot trap or neutralize it. The only way to remove radon is to physically vent it out of the building.
Do I need to mitigate if my level is 3.0 pCi/L?
The EPA strongly suggests that you consider fixing your home if your long-term levels sit between 2.0 and 4.0 pCi/L. While it is below the EPA action level, reducing your exposure to any known carcinogen is always the safest choice.
Can radon come back after mitigation?
Yes. Radon levels can change over time due to weather, seasonal conditions, foundation shifts, or changes to your home’s ventilation. Even after mitigation, regular testing is recommended to ensure levels stay low.
Should I test my home again after renovations or remodeling?
Yes. Renovations that affect your foundation, insulation, ventilation, or airflow patterns can change how radon enters and moves through your home. It’s a good idea to retest after major remodeling projects, especially in basements or lower levels.
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