Question 1

What is radon gas?

Accepted Answer

Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil, rock, and water. It's colorless, odorless, and tasteless — meaning you cannot detect it without testing. Radon seeps into homes through cracks in foundations, gaps around pipes, construction joints, and other openings in contact with the ground. Outdoors, radon disperses harmlessly, but indoors it can accumulate to dangerous concentrations.

Question 2

Why is radon dangerous?

Accepted Answer

Radon is the #2 leading cause of lung cancer in the United States, responsible for an estimated 21,000 deaths per year according to the EPA. When you breathe in radon, radioactive particles can get trapped in your lungs. Over time, these particles damage lung tissue and can lead to lung cancer. The risk increases with higher radon levels and longer exposure times. Smokers exposed to elevated radon have an especially high lung cancer risk.

Question 3

What radon level is considered dangerous?

Accepted Answer

The EPA recommends taking action to reduce radon levels at or above 4.0 pCi/L (picocuries per liter of air). However, there is no truly 'safe' level of radon — even levels below 4.0 pCi/L carry some risk. The EPA also suggests that homeowners consider mitigation for levels between 2.0 and 4.0 pCi/L. The World Health Organization (WHO) recommends an even lower action level of 2.7 pCi/L (100 Bq/m³).

Question 4

How do I test my home for radon?

Accepted Answer

There are two main approaches to radon testing: DIY test kits and professional testing. DIY kits are available at hardware stores for $15-$40 and involve placing a detector in your home for 2-90 days, then mailing it to a lab. Professional testing uses continuous radon monitors (CRMs) that record hourly readings over 48+ hours and provide immediate, detailed results. Professional testing is recommended for real estate transactions and when accuracy is critical.

Question 5

How much does radon testing cost?

Accepted Answer

Professional radon testing typically costs $125–$400, depending on your location and the type of test. DIY test kits range from $15–$40. Professional testing with a continuous radon monitor provides more accurate and detailed results (hourly readings) and is the standard for real estate transactions. Many state health departments also offer free or low-cost radon test kits.

Question 6

How much does radon mitigation cost?

Accepted Answer

Radon mitigation systems typically cost $800–$2,500 for standard sub-slab depressurization in most homes. Crawl space systems may cost $1,200–$3,000 due to the added vapor barrier. Factors that affect cost include your home's size, foundation type, number of suction points needed, and local labor rates. The average homeowner pays around $1,200–$1,500 for a complete mitigation system.

Question 7

How does a radon mitigation system work?

Accepted Answer

The most common radon mitigation method is Active Sub-Slab Depressurization (ASD). A small hole is drilled through the basement floor or slab, PVC piping is connected and routed to the exterior of the home, and a quiet fan creates continuous suction beneath the foundation. This reverses the pressure differential that draws radon into your home, pulling the gas from beneath the slab and venting it safely above the roofline where it disperses harmlessly.

Question 8

How effective is radon mitigation?

Accepted Answer

Professional radon mitigation systems reduce indoor radon levels by 90–99% in most homes. A home with a radon level of 20 pCi/L can typically be reduced to below 2.0 pCi/L with a properly designed and installed system. Post-installation testing is always performed to verify the system is working effectively.

Question 9

Is radon testing required when buying or selling a home?

Accepted Answer

While no state mandates radon testing during a home sale, over 37 states require sellers to disclose known radon test results. The EPA strongly recommends testing every home before purchase. In practice, radon testing has become a standard part of home inspections in most high-risk areas. If elevated levels are found, buyers typically negotiate mitigation as part of the sale — either as a seller repair or a price credit.

Question 10

Can I do radon mitigation myself (DIY)?

Accepted Answer

While it's technically possible to install a radon mitigation system yourself, it is strongly recommended to use a certified professional. Improper installation can fail to reduce radon levels adequately or even make the problem worse. Certified professionals understand diagnostic techniques, proper suction point placement, fan sizing, and sealing methods. Additionally, many states require radon mitigation contractors to be licensed, and DIY systems may not satisfy real estate transaction requirements.

Question 11

How long does a radon mitigation system last?

Accepted Answer

The piping and structural components of a radon mitigation system can last 20+ years with no maintenance. The radon fan — the only moving part — typically lasts 7-12 years before needing replacement. Fan replacement costs $200-$350 installed. Every system includes a U-tube manometer that provides a visual indicator of whether the fan is working. The EPA recommends retesting your home every 2 years to ensure the system continues to perform effectively.

Question 12

Does radon affect every home?

Accepted Answer

Radon can affect any home — old or new, with or without a basement, in any state. The EPA estimates that nearly 1 in 15 homes in the United States has elevated radon levels. Radon levels can vary dramatically from one home to the next, even between neighboring houses, because they depend on the specific geology beneath each foundation. The only way to know your home's radon level is to test it.

Question 13

What is the EPA action level for radon?

Accepted Answer

The EPA action level for radon is 4.0 pCi/L (picocuries per liter of air). At or above this level, the EPA recommends installing a radon mitigation system. However, the EPA also states that radon levels below 4.0 pCi/L still carry some risk, and homeowners should consider mitigation between 2.0–4.0 pCi/L. For context, the average outdoor radon level is about 0.4 pCi/L, and the average indoor level in U.S. homes is about 1.3 pCi/L.

Question 14

Do new homes need radon testing?

Accepted Answer

Absolutely. New homes can have just as high — or higher — radon levels as older homes. Even homes built with radon-resistant new construction (RRNC) features should be tested after occupancy. RRNC features like sub-slab aggregate, vapor barriers, and passive vent pipes are a great foundation, but the EPA recommends testing to determine if an active fan needs to be added to the passive system.

Question 15

How long does radon mitigation take to install?

Accepted Answer

Most radon mitigation systems can be installed in 3-5 hours by a certified professional. Standard sub-slab depressurization systems are typically completed in a single day. Crawl space systems may take 4-8 hours due to the additional work of installing the vapor barrier. The system is operational immediately after installation, and post-mitigation testing is recommended within 24-48 hours.

Question 16

Will a radon system affect my energy bills?

Accepted Answer

Minimally. A radon mitigation fan typically consumes 40-90 watts of electricity — comparable to a standard light bulb. The annual operating cost is approximately $50-$100 per year. Because the system draws air from beneath the foundation rather than from your conditioned living space, the impact on heating and cooling costs is negligible.

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