How to Get Rid of Radon in Your House: A Practical Guide to Safer Air

Radon is one of those things you do not see, smell, or taste, but it can quietly build up in your home and increase your risk of lung cancer over time. I have spent years working on indoor air quality issues, and radon is the one that surprises people the most. They know about mold, carbon monoxide, maybe even VOCs from paint. But radon? That is radioactive gas seeping up from the ground beneath their basement slab.

The good news is that radon is manageable. Once you understand where it comes from and how it moves, you can take real steps to lower the levels in your living space. This article walks through the practical side of radon mitigation, from testing to choosing the right system for your home.

Why Radon Gets Into Your House

Radon forms naturally when uranium in soil and rock breaks down. It is a gas, so it migrates upward through the ground. When a house sits above that soil, the gas can enter through any opening in the foundation. Cracks in the basement slab, gaps around pipes, sump pump openings, and even the tiny pores in concrete block walls all serve as entry points. Once inside, radon gets trapped and can concentrate to levels that pose a health risk.

The EPA and Health Canada both have clear guidelines on what they consider an actionable level. If your test shows radon at or above 4 picocuries per liter (pCi/L) in the United States, or 200 becquerels per cubic meter (Bq/m³) in Canada, you need to act. Many homes in certain regions test well above that, and the fix is often simpler than people expect.

Start with a Reliable Radon Test

Before you spend any money on equipment or contractors, you need to know your baseline. A radon testing kit is cheap and widely available. You can buy one at a hardware store, online, or through your local public health department. Short-term tests sit in your home for two to seven days and give you a snapshot. Long-term tests, which last three months to a year, give a more accurate average. I always recommend starting with a short-term test for speed, then following up with a long-term test if the results are borderline.

Place the test in the lowest livable area of your home, usually the basement. Follow the instructions exactly: keep windows and doors closed for at least twelve hours before and during the test period. Do not place it near drafts, heat sources, or high humidity. A radon sensor can also give you continuous readings over time, which is helpful if you want to see how levels change with weather and seasons.

Once you have your results, you can decide on the best radon mitigation strategy. The approach depends on your home's foundation type, the radon level, and your budget.

The Core Strategy: Sub-Slab Depressurization

For most homes with a basement or a concrete slab, the most effective method is sub-slab depressurization, often called soil suction. This technique creates negative pressure under the slab so that radon is pulled from the soil and vented safely above the roof line, never entering your living space.

A contractor drills a small hole through the basement slab, typically three to four inches wide. They dig out a pit below the slab and fill it with crushed stone to create an air pocket. A pipe runs from that pit up through the house and out the roof. A radon fan, mounted in the attic or outside, draws air from under the slab and pushes it out. This is called an active radon system because it uses a fan. A passive radon system relies on natural air pressure differences and does not use a fan, but it is less reliable in many homes.

Active systems work well because they run continuously. The fan is usually quiet and draws very little electricity. I have installed these in houses where radon levels dropped from 20 pCi/L to below 2 pCi/L within a day. That is a dramatic improvement for a relatively straightforward installation.

What About a Sump Pump?

If your basement has a sump pump pit, that can be a major radon entry point. The pit is open to the soil, and radon flows in easily. Sealing the pit cover with a gasket and caulk helps, but sometimes the best approach is to integrate the sump into the sub-slab depressurization system. A contractor can connect the sump pit to the vent pipe and fan, so it becomes part of the suction network.

Other Methods That Support Mitigation

Sub-slab depressurization is the heavy lifter, but it works better when you combine it with other measures. Crack sealing is one of the most straightforward. Walk around your basement with a tube of sealant and fill every visible crack in the foundation walls and the basement slab. Pay special attention to the joint where the floor meets the wall. That gap is a common radon highway. Use a polyurethane or silicone-based sealant designed for concrete. It is cheap and takes an afternoon.

Plastic sheeting, also called a radon membrane, can be laid over exposed soil in crawl spaces or unfinished basements. This creates a physical barrier that slows the gas from moving into the air. It is not a complete solution on its own, but it helps a lot when combined with ventilation improvement and a depressurization system.

Ventilation improvement simply means bringing in more fresh outdoor air and exhausting stale indoor air. An air exchanger, also known as a heat recovery ventilator, can do this efficiently without wasting energy. It pulls in fresh air and pushes out stale air while transferring heat between the two streams. This dilutes the radon concentration and improves overall air quality. It is especially useful in tight, energy-efficient homes where radon can build up quickly.

For homes with a crawl space instead of a full basement, the approach shifts a little. You can still do soil suction by laying a perforated pipe in a bed of crushed stone under a vapor barrier, then venting it with a fan. The same principles apply, just adapted for a shallower space.

How to Get Rid of Radon in Your House: The Step-by-Step

If you are reading this and wondering where to start, here is the practical sequence I have seen work time and again. First, test with a radon testing kit. Second, if the result is high, bring in a qualified contractor who specializes in radon mitigation. A general handyman or a home inspection company may not have the specific experience. Look for someone certified by the National Radon Proficiency Program or similar body in your region. They will know how to design an active radon system that fits your foundation type.

Third, seal all major entry points: cracks, pipe penetrations, and the sump pump pit. Fourth, install the sub-slab depressurization system with a radon fan and route the vent pipe above the roofline. Fifth, retest after the system is running. Most contractors will include a follow-up test to confirm the levels have dropped. If you are in an area with very high radon, you might also consider a continuous radon sensor for ongoing monitoring.

That is the essence of how to get rid of radon in your house. It is not a mystery, and it does not require a total renovation. It takes some targeted work and a bit of investment, but the peace of mind is worth it.

Active Versus Passive Systems: Which One for You?

A passive radon system relies on natural convection and wind to pull air through the vent pipe. It has no fan and no moving parts. It costs less to install and nothing to run, but it is also less reliable. In warm weather or calm conditions, the natural draft may not be strong enough to move the radon out. I have seen passive systems work well in some houses and fail completely in others. If your radon levels are only slightly above the action limit, a passive system might be enough. But if they are high, go active.

An active radon system costs more upfront because of the fan and wiring, but it delivers consistent results. The fan itself is a small appliance that runs 24/7. It uses about as much electricity as a 60-watt light bulb. Many homeowners I have worked with say the monthly cost is negligible compared to the health benefit. The fan should be rated for continuous operation and mounted outside the living space, usually in the attic or on an exterior wall, to keep noise down.

Costs and Contractor Considerations

Installing a radon mitigation system usually costs between $1,500 and $3,000 in the United States, depending on the complexity of the job and your region. That includes the fan, piping, labor, and a post-mitigation test. Sealing cracks and replacing a sump pump cover might add a few hundred dollars. If you are handy, you can do some of the sealing yourself, but I strongly advise leaving the depressurization system to a pro. Mistakes in pipe routing or fan placement can make the system ineffective or even create a backdraft hazard with other appliances.

When you talk to contractors, ask about their experience with radon specifically. Not every basement waterproofing company knows radon. A good contractor will inspect your basement slab, check the soil type under your house, and explain their plan before they drill. They should also be willing to show you past test results from similar jobs.

Long-Term Monitoring and Maintenance

Once your system is installed, do not just forget about it. Radon levels can change over time if the ground shifts, the foundation settles, or the fan wears out. Test every two years with a radon testing kit, or install a radon sensor that gives you live readings. Some sensors connect to your phone and alert you if levels spike. That is a nice layer of protection.

If you buy a house with a pre-existing mitigation system, ask for the test results and check that the fan is still running. I have walked into homes where the previous owner installed a system but never turned the fan on. The radon levels were back up to dangerous numbers. A running fan is the only thing keeping the gas out.

Understanding how to get rid of radon in your house is not something you need to be an engineer to grasp. It comes down to knowing your levels, sealing the paths, and creating suction under the slab. The steps are proven, the materials are standard, and the results are measurable. If you have a basement or a slab on grade, this is one of the most important things you can do for your family's health. Test it. Fix it. Retest. Then breathe easier.