Radon is a radioactive gas with no color and no smell, and it forms on its own as uranium inside soil and rock breaks apart. The gas works its way up through the ground and into buildings. Indoors it can gather to levels that matter for your health over the long run. The EPA, the Centers for Disease Control and Prevention (CDC) and the American Cancer Society all rank radon as the second leading cause of lung cancer in the United States. Pennsylvania carries a well-earned reputation for high indoor radon, and homeowners in York County have solid reasons to pay attention.
Why York County Has a Radon Problem
The Environmental Protection Agency (EPA) sorts every county in the nation into one of three radon zones, using geology, soil data and indoor measurements. York County falls into Zone 1, the category with the highest predicted indoor radon potential. The county lies in the Piedmont region of Pennsylvania, where the bedrock and the soil weathered from it hold small amounts of uranium. As that uranium breaks down, it gives off radon into the ground below homes.
Zone 1 does not mean your house is high. Radon depends on what sits directly beneath your particular foundation, how tightly the house was built, and how air moves around inside it. Two homes on the same York street can post completely different numbers. That is exactly why the EPA recommends testing every home instead of guessing from the map.
How Radon Gets Into a York Home
Houses pull air out of the soil, especially in cold weather, when warm indoor air rises and leaks out the upper floors. That creates gentle suction down at the foundation. The usual ways in include:
- Cracks across the basement slab and gaps where the floor meets the wall.
- Sump pits left open or covered with a lid that does not seal.
- Hollow cores running through concrete block foundation walls.
- Fieldstone and rubble walls under older homes in the city.
- Openings around plumbing, electrical and utility penetrations.
- Dirt or gravel crawl spaces with no sealed membrane over them.
What Your Radon Number Means
Radon in air gets measured in picocuries per liter (pCi/L), or in becquerels per cubic meter (Bq/m³) outside the United States, where 1 pCi/L equals 37 Bq/m³. These are the 3 reference points the EPA works from:
- 4.0 pCi/L or higher: the EPA recommends fixing the home with a mitigation system.
- 2.0 to 4.0 pCi/L: the EPA suggests weighing a system, since no level is proven safe.
- Below 2.0 pCi/L: a good result, though you should still retest now and then and after big changes to the house.
For comparison, the EPA puts the average indoor level across the United States at roughly 1.3 pCi/L (48 Bq/m³), against about 0.4 pCi/L (15 Bq/m³) in outdoor air. The Pennsylvania Department of Environmental Protection (DEP) (opens in a new tab) reports that approximately 40% of homes tested in Pennsylvania are above the 4 pCi/L action level. The EPA guide to the health risk of radon (opens in a new tab) explains how long-term exposure ties into lung cancer.
When to Test in York
Test if you never have. Test if you are buying or selling, using the steps in our real estate radon testing guide. Test before you finish a basement, and test again once two years have passed since the last one, system or no system. A professional radon testing visit from a PA DEP-certified tester runs a continuous monitor for at least 48 hours with the house closed up. You get hourly data instead of one flat average.
What Happens If Your Level Is High
The most effective and most common fix is active soil depressurization. A radon system installation sets a suction point below the slab and ties it to sealed pipe and an inline fan. The fan pushes the gas out above the roofline. Homes with a sump pit or a finished lower level usually need basement radon mitigation built around a sealed, serviceable sump lid.
Once the fan is running, a follow-up test records your new level. From there, glance at the manometer monthly and retest at least every two years. If a later test starts creeping upward, a radon system repair visit from our certified crew can track down why.
When your number comes back high, Radon Mitigation York, a PA DEP-certified mitigation firm, will call to talk through your result and give you a free written estimate.
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