Radon testing in York County: kits, monitors and what the number means

What a pCi/L is, the difference between a $20 kit and a certified test, the best month, and when to hire a tester instead.

Every mitigation job starts with a number. This is how to get a good one.

The units

Radon is measured in picocuries per litre of air, written pCi/L. The EPA action level is 4.0 pCi/L: fix the house at or above that. The EPA also says to consider fixing between 2.0 and 4.0, and the World Health Organization uses 2.7 as its reference. There is no level at which risk is zero; outdoor air is around 0.4. York County basements average well above 4.0, so a high result is the normal case here, not the exception.

Kinds of test

• Short-term charcoal kit. $15 to $30 from a hardware store or the state programme, left out for two to seven days, mailed to a lab. Fine for a first look. Results swing with weather.
• Long-term alpha-track kit. $25 to $50, left out for 90 days to a year. The most accurate picture of what you actually breathe, and the right follow-up to a borderline short-term result.
• Continuous radon monitor. An electronic instrument set by a DEP-certified tester for 48 hours or more, logging hourly readings and tamper conditions. This is the real-estate test; a report from one is what buyers, sellers and agents accept.
• Consumer digital monitors. $150 to $250 and useful for watching trends after mitigation, but not accepted for a sale.

When to test

• January or February. Closed-house conditions give a near worst-case number, which is what you want. The DEP runs National Radon Action Month in January for this reason.
• Before a sale, and during one. Sellers who test first avoid surprises; buyers should test regardless.
• After mitigation. A day to a month after the fan goes on, then every two years.
• After any big change. A new furnace or air conditioner, a finished basement, foundation work, a new addition.

Closed-house conditions mean windows and exterior doors shut for twelve hours before and throughout the test, with normal use of entry doors. Running the whole-house fan or leaving a basement window open invalidates the result.

Who may test

In Pennsylvania, a homeowner may test their own home with a kit. Anyone testing someone else's home for pay, including a home inspector, must hold a DEP testing certification, which is separate from the mitigation certification. Several firms on this site test only; their listings say so under radon testing and inspection. Expect $150 to $300 for a certified 48-hour test in York County.

Keep the tester separate

For a real-estate test, and for the post-mitigation clearance especially, it is better if the person measuring is not the person who sold you the system. Mitigators are allowed to run the post-test, and many do it well, but an independent number is worth the extra $150 when several thousand dollars of negotiation or a guarantee depends on it.

Last updated 2026-09-28. General information for the York area, not professional advice; confirm specifics with a qualified contractor or your insurer.