Radon is a naturally occurring radioactive gas produced by the breakdown of uranium in soil, rock, and water. It is colorless, odorless, and tasteless — making it impossible to detect without specialized equipment.

Radon gas moves up through the ground and into your home through cracks and openings in the foundation. Every home has some level of radon. The question is whether the concentration is high enough to pose a health risk.

According to the U.S. Environmental Protection Agency (EPA), radon is the second leading cause of lung cancer in the United States, responsible for an estimated 21,000 lung cancer deaths each year. Only smoking causes more lung cancer deaths.

Radon typically enters a building through the lowest level that is in contact with the ground. The air pressure inside your home is usually lower than the pressure in the soil around your foundation, creating a vacuum effect that draws radon gas indoors.

Common entry points include:

• Cracks in solid floors and walls
• Construction joints where the floor meets the wall
• Gaps around service pipes and wiring
• Sump pump openings and floor drains
• Crawl spaces that open directly to the soil
• Cavities inside walls (especially block foundations)

Any home can have elevated radon — new or old, with or without a basement, well-sealed or drafty. The only way to know your radon level is to test.

When you breathe in radon, radioactive particles get trapped in your lungs. Over time, these particles release small bursts of energy that can damage lung tissue and lead to lung cancer. The risk increases with the concentration of radon and the duration of exposure.

According to the EPA and the National Academy of Sciences:

• Radon causes approximately 21,000 lung cancer deaths per year in the U.S.
• It is the #1 cause of lung cancer among non-smokers
• Smokers exposed to elevated radon have an even greater risk — up to 10 times higher than non-smokers
• There are no immediate symptoms — radon-related lung cancer develops over years of exposure

Radon testing is the only way to determine the radon concentration in your home. The EPA and the New York State Department of Health (NYSDOH) both recommend that every home be tested, regardless of its age or location.

Types of Radon Tests

Testing Conditions

For accurate results, closed-house conditions must be maintained during the test:

• Keep all windows and exterior doors closed (except for normal entry/exit)
• Do not operate whole-house fans or window fans
• Normal HVAC operation is fine
• Begin closed-house conditions at least 12 hours before the test starts

Radon levels are measured in picocuries per liter (pCi/L). Here's how to interpret your results:

Radon mitigation is the process of reducing radon concentrations in indoor air. The most common and effective method is Active Soil Depressurization (ASD), also called sub-slab depressurization.

How ASD Systems Work

1. Suction Point: A hole is drilled through the foundation slab into the aggregate or soil below.
2. PVC Piping: A sealed PVC pipe is installed from the suction point, routed through or along the building, and vented above the roofline.
3. Radon Fan: An inline fan creates continuous negative pressure beneath the slab, drawing radon gas out before it enters the living space.
4. Exhaust: The radon-laden air is safely exhausted above the roof where it quickly dilutes to harmless concentrations.

Effectiveness

A properly designed ASD system can reduce radon levels by up to 99%. Post-mitigation testing is always performed to verify the system is working correctly. Most installations are completed in a single day.

While airborne radon is the primary concern, radon can also dissolve in groundwater — particularly in homes served by private wells. When water containing radon is used for showering, dishwashing, or laundry, the gas is released into the indoor air.

The EPA estimates that radon in water causes approximately 168 cancer deaths per year in the United States — mostly from lung cancer caused by inhaling radon released from water, and a smaller number from stomach cancer caused by ingesting radon-contaminated water.

Should You Test Your Water?

If your home has a private well (not public/municipal water), you should test for radon in water, especially if:

• Your indoor air radon test shows elevated levels
• Your home is in a known high-radon area (most of the Hudson Valley qualifies)
• You are buying or selling a home with well water

Public water supplies that use surface water (reservoirs, rivers) are generally not a concern because radon dissipates into the air before reaching your tap. However, public systems using groundwater wells may still contain radon.

The EPA classifies counties into three radon zones based on predicted average indoor radon levels. The Hudson Valley region contains several of the highest-risk areas in New York State.

Radon testing has become a standard part of the home buying process in New York. Many lenders — including VA, FHA, HUD, and conventional mortgage providers — require or strongly recommend radon testing before closing.

For Home Buyers

• Include radon testing as part of your home inspection contingency
• Insist on professional CRM testing — DIY kits are not accepted for most closings
• If radon is elevated, mitigation can often be negotiated as part of the sale
• A properly installed mitigation system can reduce levels by up to 99%

For Home Sellers

• Testing proactively shows good faith and avoids delays at closing
• If levels are elevated, installing a mitigation system before listing can be used as a selling feature
• New York State requires sellers to complete the Property Condition Disclosure Statement, which includes a radon question

For Real Estate Professionals

We work directly with realtors, home inspectors, and attorneys throughout the Hudson Valley. Our turnaround is fast, our reports are lender-ready, and our ELAP certification ensures your transactions proceed smoothly.

Every January, the EPA and state health departments across the country promote National Radon Action Month — a campaign to raise awareness about radon and encourage testing.

January is an ideal time to test because:

• Windows are typically closed during winter, allowing radon to accumulate indoors
• Radon levels tend to be highest during colder months due to the stack effect (warm air rising creates suction on the soil)
• Testing in winter gives a conservative (higher) estimate, which is better for decision-making

However, radon can be tested any time of year. Don't wait for January if you haven't tested your home — schedule a test today.