Why High Radon in Pennsylvania Demands a Proactive Approach for Homeowners

Understanding the Risk Beneath Your Home

Living in Pennsylvania means sharing the landscape with a silent, invisible hazard that sits right under our feet. I have spent years working with homeowners in York PA and across the state, and the one question I hear most often is, "Is radon really that big of a deal here?" The short answer is yes, and the reasons go back to the geology and the housing stock we have inherited. The issue of high radon in Pennsylvania is not a scare tactic. It is a real, measurable problem that affects thousands of homes, especially in the southeastern part of the state where York PA is located.

The EPA has mapped radon potential zones across the country, and nearly every county in Pennsylvania falls into Zone 1, the highest risk category. That means the average indoor radon level in these homes is expected to exceed the EPA action level of 4 picocuries per liter. I have tested homes in York PA that registered over 20 pCi/L, and some even higher. The health effects of radon are well documented: prolonged exposure is the second leading cause of lung cancer after smoking. This is not a problem you want to ignore, and it is not one you can solve by simply opening a window or buying a houseplant.

Why Pennsylvania Homes Are Especially Vulnerable

Pennsylvania sits on a foundation of granite, shale, and limestone that naturally contains uranium. As uranium decays, it releases radon gas, which then migrates through the soil and into the air. That is the source of soil gas, the primary way radon enters a building. The way our homes are built matters a great deal. Many older homes in York PA have basements with poured concrete floors, often with cracks, gaps around pipes, and no vapor barrier underneath. Newer homes are not automatically safe either. Radon-resistant construction techniques have improved, but not every builder follows them, and even a well-sealed foundation can still draw in radon through the stack effect, where warm indoor air rises and pulls soil gas up from below.

I once inspected a charming 1920s house in downtown York PA. The owners had finished the basement into a family room, complete with carpet and drywall. They had never tested for radon. When we ran a radon testing kit in the lowest livable level, the result came back at 18 pCi/L. The problem was not that the house was old. It was that the basement floor had settled over the decades, creating hairline cracks that acted like highways for radon. The finished walls hid those cracks completely. The homeowners were shocked, but they were also relieved to catch it before they spent years breathing that air.

Testing Is the Only Way to Know

You cannot smell, see, or taste radon. That is why the EPA and the National Radon Program recommend testing every home, regardless of age or location. A simple radon testing kit costs about $15 to $30 and takes three to seven days to complete. Short-term tests give you a snapshot, but I always advise homeowners to follow up with a long-term test, which runs for at least 90 days and gives a truer average of year-round exposure. Testing is the first step, and it is the only way to know whether you need radon mitigation.

If the test comes back above 4 pCi/L, the EPA says you should take action. But I have worked with many families who chose to mitigate at levels as low as 2.7 pCi/L because they had young children or elderly relatives at home. There is no safe level of radon. The goal is to get it as low as reasonably achievable. That is where professional radon mitigation comes in.

How Radon Mitigation Works in Practice

The most common and effective method for reducing radon levels is sub-slab depressurization. A contractor drills a small hole through the basement floor, digs a pit below the slab, and installs a pipe that runs up through the house and out the roof. At the bottom of that pipe, a sump pump is not needed because the system relies on a radon fan mounted in the attic or on the exterior. That fan creates negative pressure under the slab, pulling soil gas away from the foundation and venting it safely above the roofline. The hole around the pipe is sealed with radon sealant to prevent the gas from sneaking back inside.

I have seen this system work in houses of every shape and size in York PA. In one case, a rancher with a crawlspace instead of a basement required a different approach. We installed a vapor barrier over the dirt floor, sealed it to the walls, and ran the vent pipe through the crawlspace to an exterior fan. The reduction was dramatic: from 12 pCi/L down to 1.2 pCi/L. The homeowners could finally use their basement for storage without worrying about the air they were breathing.

Another technique that sometimes gets overlooked is basement ventilation. If the basement is used as a livable space, increasing the air exchange rate with a heat recovery ventilator can help dilute radon levels. But ventilation alone is rarely enough in a home with high radon in Pennsylvania. The soil gas is constantly being generated, and without a physical barrier or active suction, it will keep finding its way inside.

What to Expect During a Home Inspection

If you are buying a home in York PA, a standard home inspection usually does not include radon testing. You have to request it separately. I always tell buyers to ask the seller for any previous test results and to run their own test during the due diligence period. If the levels are high, you can negotiate for a mitigation system to be installed before closing. A properly installed system with a mitigation system warranty gives you peace of mind and adds value to the property.

Renters face a different challenge. Landlords in Pennsylvania are not required by state law to test for radon or to disclose known levels. As a renter, you can buy a radon testing kit and test your own unit. If the results come back high, you have the right to ask your landlord to take action. Some landlords will cooperate, especially if you explain the health effects of radon and the liability they could face. Others may push back, but the health of your family is worth the conversation.

Materials and Maintenance

One question I get often is whether activated carbon filters can help with radon. The answer is no. Activated carbon is used in some water filtration systems to remove radon from well water, but it does nothing for radon in the air. For airborne radon, the solution is always about stopping the entry point or venting the gas outside. The materials used in a mitigation system are simple but critical: PVC pipe, a reliable radon fan, and high-quality radon sealant. The fan is the heart of the system. It has to run continuously, and most manufacturers rate them for five to ten years of service. I recommend checking the manometer, a gauge that shows the system is under pressure, at least once a month. If the gauge drops, something is wrong, and you need a service call.

The Bigger Picture

High radon in Pennsylvania is a persistent problem that does not get the attention it deserves. I have met families who lived in their homes for twenty years without ever testing, only to discover levels that put them at serious risk. The good news is that radon mitigation is a mature, proven technology. It is not experimental. It is not prohibitively expensive. For most homes, a complete system costs between $1,200 and $2,500, depending on the complexity of the installation. That is a small price to pay for reducing your risk of lung cancer and improving the air quality in your home.

If you live in Pennsylvania, especially in York PA or anywhere in the southeastern part of the state, test your home. If the levels are high, call a licensed radon mitigation contractor. Do not wait. This is one of those problems that does not go away on its own. The soil gas will keep coming, year after year, until you break the pathway. And once you do, you can breathe easier, literally and figuratively.