Radon in York County Homes: Testing, Fixing and Who Can Do It

Radon is the one house problem you can’t see, smell or hear, which is exactly why people put it off. It’s a radioactive gas that comes up out of the ground and collects indoors, mostly in basements and lower floors. Pennsylvania has a lot of it, and York County is no exception. The good news is that testing is cheap, the fix is usually a one-day job, and the state keeps a public list of who is allowed to do the work.

Why It’s So Common Here

The Pennsylvania Department of Environmental Protection says about 40% of homes tested in the state come in above the federal action level (PA DEP, Radon in the Home). A U.S. Geological Survey study of more than half a million Pennsylvania tests found that the rock and groundwater settings with the highest typical readings sit mostly in the south-central part of the state, which is our part of the map (USGS, 2013). DEP’s own guide says levels vary from one neighborhood to the next, mainly because of geology and how houses are built (DEP Radon Resource Guide, 2025).

DEP publishes test results by ZIP code, and the York numbers are worth a look. In the 17404 ZIP, 5,124 basement tests have been reported to DEP, and they average 7.7 pCi/L, nearly twice the action level. The highest single result there was 534. First-floor tests in 17404 average 4.4. In 17401, a much smaller set of 206 basement tests averages 4.3 (PA DEP radon data by ZIP code, tests from 1990 through 2025). For comparison, DEP puts the average Pennsylvania basement at about 7.1 pCi/L. These are short tests run with the house closed up, which DEP notes tend to read higher than a full year of normal living, and DEP’s own advice next to the numbers is blunt: don’t rely on your ZIP code, test your own house.

York County has shown up on DEP’s radar before. In 2018, DEP and the American Lung Association mailed free test offers to 1,526 homeowners in Peach Bottom Township, part of a push aimed at areas where past tests had come in very high (DEP release via TMIA, 2018). That doesn’t tell you anything about your house, though. Two houses on the same street can test very differently. USGS says plainly that its regional numbers can’t predict the level in any one home. The only way to know is to test.

The Number That Matters: 4 pCi/L

Radon is measured in picocuries per liter of air, written pCi/L. The EPA action level, which DEP uses too, is 4 pCi/L. At or above it, the advice is to fix the house. EPA also says to consider fixing between 2 and 4 (EPA Home Buyer’s and Seller’s Guide to Radon, 2024). So a 3.5 isn’t a gold star. It’s a judgment call you make with the number in hand.

Short Tests and Long Tests

EPA sorts tests into two kinds. Short-term tests stay in the house from 2 to 90 days, depending on the device. Long-term tests stay more than 90 days and give a better picture of your average over the seasons (EPA, 2024). DEP says a do-it-yourself kit runs about $20 to $30 at a hardware or home store, or you can hire a certified tester (PA DEP).

For most people the order goes like this:

1. Start with a short-term test in the lowest lived-in level of the house, with windows and doors closed.
2. If it reads 4 or higher, test again. DEP suggests a long-term test for results of 4 to 8 to get a better sense of the yearly average.
3. Fix the house if the follow-up is still 4 or higher.
4. Keep testing every couple of years. DEP recommends a test about once every two years, ideally in the basement during heating season, when the house is closed up (PA DEP).

Testing When You Buy or Sell

Pennsylvania has no law that requires a radon test on a house, for a sale or otherwise (DEP Radon Resource Guide, 2025). The seller’s disclosure form does ask whether the house was tested and what the result was, but a seller who never tested doesn’t have to start (LancasterHome.com summary). In practice, most buyers test during the inspection window.

A sale doesn’t leave time for a year-long test, so EPA lays out faster options. A tester can run two short-term tests side by side for at least 48 hours, run two back to back, or use a continuous monitor for at least 48 hours. If the average comes in at 4 or more, EPA’s advice is to fix it (EPA, 2024). Who pays for the system is a negotiation, not a rule. Ask your agent how they’ve seen it handled.

How the Fix Works

Most homes get a system called sub-slab depressurization. The installer drills through the basement floor, sets a PVC pipe into the soil underneath, and runs it up and out to a fan that pulls air from under the slab and vents it outside. EPA describes it as a system of vent pipes and fans that keeps radon from coming in through the floor and the foundation (EPA, 2024). The exhaust should come out above the roof line (UGA Extension, 2025).

DEP says installation should take less than a day. You’ll end up with a small gauge on the pipe called a U-tube manometer, and checking it is how you know the fan is running (PA DEP). Older houses with odd footprints, crawl spaces or additions take more planning, and that’s where a good mitigator earns the fee. You can see the radon companies listed in our directory on the radon mitigation page.

What It Costs

I won’t give you a York County price, because I haven’t seen a source that publishes one. The most recent published range I found comes from the University of Georgia Extension, which cites EPA: the average mitigation costs about $1,500, with a range of roughly $900 to $3,000, depending on how complicated the house is, the radon level and local labor and materials (UGA Extension, 2025). That’s a national range, so treat it as a yardstick. Get two written quotes and compare what each one includes, like the number of suction points and where the pipe runs.

Check the Certification

Here’s the part I’d never skip. In Pennsylvania, anyone who places radon tests, installs mitigation systems or analyzes test devices has to be certified by DEP under the Radon Certification Act. Firms are certified separately from individuals, and a certified firm has to have at least one certified person responsible for the work (PA DEP, Radon Certification).

Looking someone up takes a few minutes:

• Open DEP’s Radon Services Directory. It has lists of certified testers, mitigators and labs, sorted by name and by county, updated monthly (DEP Radon Services Directory).
• Ask for their DEP ID number. DEP’s directory notes that employees of listed mitigation firms have ID numbers in the 7000 series and testing-firm employees in the 8000 series (DEP Radon Services Directory).
• Call if you’re unsure. DEP’s toll-free line is (800) 237-2366 (DEP Radon Resource Guide, 2025).

One wrinkle if you’re on a well: DEP doesn’t certify radon-in-water testing. It only lists who offers it (PA DEP, Radon Certification).

Test Again After the Fix

A system isn’t done until the follow-up test says so. DEP says the installer should run a test after the system has been on for at least 24 hours (PA DEP). EPA suggests having that check done by an independent tester, which makes sense to me, since nobody should grade their own homework (EPA, 2024). After that, glance at the manometer now and then, and put a radon test on the calendar every two years.