For quickly Reducing radon levels, immediately increase natural ventilation by opening windows on the lowest floors and running fans. However, for long-term safety, install an Active Soil Depressurization (ASD) system. This permanent, professional fix draws gas from beneath your foundation and vents it safely outdoors, reliably cutting levels by 80 to 90%.
Radon is a naturally occurring radioactive gas. It forms when uranium breaks down in soil and rock, then seeps into homes through foundation cracks, sump pits, and gaps around pipes. The U.S. Surgeon General and EPA identify radon as the second-leading cause of lung cancer in the United States, after smoking. Reducing radon levels isn’t optional once a test confirms elevated readings it’s a health necessity.
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Why Reducing Radon Levels Matters
Radon gas is classified by the EPA and World Health Organization as a Class A human carcinogen. There is no safe threshold for long-term exposure, but the EPA sets 4.0 pCi/L as the action level that triggers a mitigation recommendation.
Long-term exposure to elevated radon increases lung cancer risk, particularly for smokers, whose risk multiplies when combined with radon exposure. Homes with unfinished basements, homes built on granite or shale bedrock, and homes with poor foundation sealing tend to show higher concentrations. You can read more about what makes radon dangerous and how exposure affects the body over time.
How Do You Know If Your Radon Levels Are High?
The only way to know your home’s radon concentration is to test it. Short-term test kits measure levels over 2–7 days; long-term kits measure over 90 days or more for a more accurate annual average.
Continuous radon monitors, used by professionals, provide hour-by-hour data and are less prone to tampering or weather-related spikes. Weather conditions especially barometric pressure changes and heavy rain can temporarily elevate readings, so understanding how testing conditions affect results matters before drawing conclusions from a single test.
If your result comes back at or above 4.0 pCi/L, retest to confirm, then schedule mitigation.
Quick and Effective Methods for Reducing Radon Levels
1. Sub-Slab Depressurization (Most Effective)
Sub-slab depressurization (SSD) is the gold-standard method endorsed by the EPA and ANSI/AARST radon mitigation standards. A licensed technician drills a hole through the foundation slab, inserts a PVC pipe, and connects it to a radon fan.
The radon fan draws gas from beneath the slab and vents it above the roofline, away from windows and living areas. This creates negative pressure under the home, preventing radon from migrating indoors. SSD reduces radon levels by 80–99% in most homes and works on slab foundations, basements, and crawl spaces with a vapor barrier.
2. Sealing Foundation Cracks and Openings
Sealing alone rarely brings radon below the action level, but it improves the efficiency of an active mitigation system. Technicians seal:
- Foundation cracks and expansion joints
- Sump pit covers
- Gaps around utility penetrations
- Openings in crawl space vapor barriers
Sealing without depressurization is not considered adequate mitigation by the EPA. Radon gas finds new entry points once existing ones are blocked.
3. Crawl Space Encapsulation
Homes with crawl spaces benefit from a sealed vapor barrier combined with a depressurization pipe run underneath it. This method, sometimes called sub-membrane depressurization, treats radon the same way SSD does by venting gas before it reaches indoor air.
4. Ventilation and Pressure Adjustments
Increasing mechanical ventilation, such as heat recovery ventilators (HRVs), can dilute indoor radon concentrations somewhat. This is a supplementary step, not a standalone fix, and it increases energy costs. It’s rarely recommended as the primary strategy for reducing radon levels in homes above the action level.
5. Water-to-Air Radon Treatment (Well Water Homes)
Homes on private well water can have radon dissolved in the water supply, which releases into the air during showers and washing. Aeration systems or granular activated carbon filters strip radon from water before it reaches household taps. If your home uses well water, radon water testing should be part of your overall assessment.
Why DIY Radon Mitigation Falls Short
Store-bought sealants and fans can’t replicate the pressure diagnostics, pipe placement, and fan sizing that certified mitigation requires. Improper installation can pull radon into the home instead of venting it out, or fail to reduce levels at all.
The National Radon Proficiency Program (NRPP) and National Radon Safety Board (NRSB) certify professionals who follow ANSI/AARST standards for system design and post-mitigation testing. Hiring a certified contractor ensures the system is sized correctly for your home’s soil conditions and foundation type. For a closer look at why this matters, see our breakdown of DIY radon mitigation and whether it works.
What Does a Professional Radon Mitigation System Cost?
Most radon mitigation systems cost between $800 and $2,500, depending on foundation type, house size, and system complexity. Homes with multiple foundation types (slab plus crawl space, for example) may need multiple suction points, increasing cost.
Ongoing costs are minimal: a radon fan uses about the same electricity as a light bulb and typically lasts 5–10 years before replacement. For a full cost breakdown, see the cost of radon mitigation and what affects pricing.
How Long Does It Take to Reduce Radon Levels?
A professionally installed sub-slab depressurization system reduces radon levels within 24 hours of activation. Full installation, including drilling, piping, and fan setup, usually takes one day for most single-family homes.
Post-mitigation testing, conducted 24 hours to 30 days after installation, confirms the system brought levels below 4.0 pCi/L. Retesting every two years is recommended to confirm the system continues performing, since fans can fail or lose efficiency over time.
Get Certified Radon Mitigation in Milwaukee
Reducing radon levels in your home requires accurate testing, correct system design, and professional installation. Milwaukee Radon Mitigation installs ANSI/AARST-compliant sub-slab depressurization systems throughout the Milwaukee, WI area, backed by NRPP-certified technicians.
Call (414) 455-7279 to schedule a radon test or mitigation consultation today.
Frequently Asked Questions
What is considered a high radon level?
The EPA action level is 4.0 pCi/L. Levels between 2 and 4 pCi/L still carry risk, and the EPA recommends considering mitigation in that range as well.
Can opening windows reduce radon levels?
Temporarily, yes, but it’s not a permanent or reliable solution. Radon returns to previous levels once windows close, and it isn’t a substitute for a mitigation system.
Does radon mitigation completely eliminate radon?
No system removes radon entirely, but a properly installed sub-slab depressurization system typically reduces levels by 80–99%, bringing most homes well below the action level.
How often should I retest after mitigation?
Retest immediately after installation, then every two years, and after any major renovation to the foundation or HVAC system.
Is radon mitigation a one-time cost?
The system installation is a one-time cost, but fans have a service life of 5–10 years and will need periodic replacement or inspection.
Conclusion
Reducing radon levels in your home is a practical achievable goal. It starts with understanding how radon enters your living space and taking clear steps based on accurate testing. Simple actions can help but proven mitigation systems offer the most reliable results.
Whether you are addressing elevated levels for health reasons planning a home sale or simply seeking peace of mind the key is informed action. With the right approach and professional support radon can be effectively managed and your home can remain a safe comfortable place to live.
If you have questions about your specific situation or want help interpreting test results, reaching out to an experienced local provider such as Milwaukee Radon Home can make the process clearer and more manageable. Taking that first step today sets the foundation for a healthier home tomorrow.
