Understanding the Pennsylvania Radon Action Level for Homeowners in York

When I bought my first house in York, Pennsylvania, about ten years ago, the radon test was just a line item on the inspection report. I signed off without really understanding what the numbers meant. Later, after talking to a radon inspector and installing a mitigation system, I learned how important that one measurement is. The number that matters most for anyone living in Pennsylvania is the Pennsylvania radon action level. It is the threshold that tells you whether you need to take steps to reduce radon in your home.

Radon is a radioactive gas that comes from the natural decay of uranium in soil. It seeps into homes through cracks in the foundation, gaps around pipes, and other openings. Over time, breathing high levels of radon increases your risk of lung cancer. The EPA has set a national action level at 4 picocuries per liter of air. Pennsylvania, like many states, follows that same benchmark. But the real story is in the local geology. York sits on a mix of limestone and shale, which can produce elevated radon readings. That is why every homeowner here should know the Pennsylvania radon action level and test their home regularly.

How the Action Level Works

The action level is not a safety line. It is a guideline. If your test shows radon at 4 pCi/L or higher, the EPA recommends fixing your home. But even levels below 4 pCi/L carry some risk. The Pennsylvania radon action level is the same as the EPA's recommendation, but the state has its own program that provides free or low-cost test kits to residents. I have used those kits myself, and they are simple. You hang a small detector in your lowest livable level for a few days, then mail it to a lab. The results come back in a week or two.

One thing I have learned is that a single short-term test can be misleading. Seasonal changes, weather, and how much you run your HVAC all affect the reading. That is why many experts, including the radon inspector I worked with, recommend a long-term test. A long-term test sits in your home for three months to a year and gives a more accurate average. If that average is above the action level, you need a mitigation system.

Testing: The First Step

Testing is straightforward, but you have to follow the instructions. I made the mistake of placing my first radon test kit near a drafty window. The result came back low, but I later learned it was unreliable. A good test is placed in a room you use regularly, at least 20 inches off the floor, away from windows, doors, and exterior walls. You keep the house closed for 12 hours before starting the test. That means no opening windows or running exhaust fans more than usual.

If you are buying a home in York, ask for a radon test as part of the inspection. Sellers are not required to disclose radon levels in Pennsylvania, but many do. If the test comes back above the action level, you can negotiate for the seller to install a mitigation system before closing. I have seen deals fall through because buyers did not realize the cost of mitigation, which typically runs between $800 and $2,500 depending on the system.

Mitigation Options

Once you know your level, the next question is what to do. The most common and effective method for homes with basements or slab foundations is sub-slab depressurization. A contractor drills a small hole through the concrete floor, digs a suction pit underneath, and runs a pipe from that pit up through the roof. A radon fan, mounted in the attic or outside, creates constant depressurization under the slab. That pulls radon-laden soil gas away from the house and vents it safely above the roofline.

I watched my installer do this. He used a manometer after finishing to check that the system was pulling enough suction. The manometer is a simple U-tube gauge that shows pressure difference. If it reads correctly, the system is working. You can check it yourself once a month. Some systems also include a smoke test, where the contractor uses a smoke pencil to see if air is being drawn into the suction pit. That confirms there are no leaks in the seal.

There are two main categories: passive mitigation and active mitigation. Passive mitigation relies on natural pressure differences and stack effect to draw radon out. It is less reliable, especially in tight homes. Active mitigation uses a radon fan to create mechanical depressurization. That is the standard for most homes in York because our soil can produce high levels. I recommend active for anyone who tests at or above the action level.

New Construction and Radon-Resistant Construction

If you are building a new home in York, radon-resistant construction is worth the investment. It adds very little to the overall cost, maybe a few hundred dollars. The builder places a layer of gravel under the slab, covers it with a heavy plastic vapor barrier, and installs a vent pipe that runs from the gravel up through the roof. That pipe can later be connected to a radon fan if needed. This is essentially passive mitigation built in from the start. If you test later and find levels above the Pennsylvania radon action level, you can add the fan and convert it to active mitigation easily.

The Indoor Radon Abatement Act of 1988 was a federal law that aimed to reduce radon risks in buildings. It led to the EPA's Radon Program and encouraged states like Pennsylvania to set up their own testing and mitigation resources. January is National Radon Action Month, when the EPA and state agencies promote testing. I always remind friends in York to test during that month, especially if they have never tested before.

Why York Homeowners Should Pay Attention

York County has a mix of older homes with stone basements and newer developments on slabs. Older homes often have more cracks and openings, which means more radon entry. I have seen homes built in the 1800s with dirt-floor cellars that tested over 20 pCi/L. That is five times the action level. Those homes needed aggressive mitigation, including sealing all exposed earth and installing a heavy-duty radon fan.

Sealant alone is not enough. You can fill cracks in the foundation and gaps around pipes, but radon will find other paths. A combination of sealing and depressurization is the only reliable approach. The suction pit under the slab creates a low-pressure zone that draws soil gas toward the pipe instead of into your living space. That is why sub-slab depressurization is the gold standard.

If you are a renter in York, you still have a right to know about radon. Landlords are not required to test, but you can buy your own radon test kit and do it yourself. If the result is high, talk to your landlord about mitigation. Some municipalities have programs to help with costs. The Pennsylvania Department of Environmental Protection offers free test kits to residents who qualify.

Final Thoughts on Staying Safe

I have tested my own home three times over the past decade. Each time, the level stayed below the action level, but not by much. That reminds me that the action level is not a guarantee of safety. It is simply the point where the EPA says the risk is high enough to warrant action. The lower your level, the lower your risk. If you are at 2 or 3 pCi/L, you might choose to install a passive system just for peace of mind.

Testing is cheap and easy. Mitigation is a one-time expense that pays for itself in health and property value. Every home in York should be tested at least once, and preferably every two years. If you buy a test kit today and mail it in, you will have your results in a couple of weeks. That is a small effort for knowing whether you are breathing safe air.