A radon report can look simple: one number, a unit labeled pCi/L, and a recommendation. Yet that number can affect a home purchase, a repair negotiation, and your plans for protecting the people who will live there. This radon test results example explains how to read a typical report and what a result may mean for a Maryland home.
Radon is a naturally occurring radioactive gas that comes from soil and rock. It can enter through foundation cracks, sump pits, utility openings, and other pathways at the lowest levels of a home. Because it is colorless and odorless, testing is the only reliable way to know whether elevated levels are present.
A Radon Test Results Example
Here is a simplified example of what a short-term real estate radon test report may show:
Property: Single-family home with a finished basement Test location: Basement, lowest livable level Test period: 48 hours Test method: Continuous radon monitor Average result: 4.6 pCi/L Maximum recorded reading: 6.1 pCi/L Minimum recorded reading: 2.9 pCi/L Closed-house conditions: Met during the test Recommendation: Consult a qualified radon mitigation professional
The most important number is usually the average result: 4.6 picocuries per liter of air, written as pCi/L. The U.S. Environmental Protection Agency recommends taking action to reduce radon when a result is at or above 4.0 pCi/L. A reading of 4.6 pCi/L does not mean the home is unsafe to enter or that a sale must stop. It does mean the result deserves a practical response, usually a mitigation estimate and a discussion of next steps.
A continuous monitor may also show hourly readings, temperature, humidity, and device movement or power data. Those details help confirm that testing conditions were appropriate and that the result is credible.
What Common Radon Numbers Mean
Radon readings are not pass-or-fail in the same way as a smoke alarm or a GFCI outlet. They represent a concentration that can vary over time. Weather, HVAC operation, wind, barometric pressure, and how the home is used can all affect the reading.
Below 2.0 pCi/L
A result below 2.0 pCi/L is generally considered low. No radon level is completely risk-free, but a low reading normally does not call for mitigation. Keep the report with your home records and consider retesting in the future, particularly after major renovations, changes to the HVAC system, or conversion of an unfinished basement into living space.
For example, a 1.1 pCi/L result from a properly conducted 48-hour test is reassuring. It tells a buyer that the tested level was low under the conditions present during that test period.
Between 2.0 and 3.9 pCi/L
This middle range is where context matters. The EPA recommends considering mitigation for readings between 2.0 and 4.0 pCi/L. A 2.7 pCi/L result is below the primary action level, but it is not a reason to ignore radon altogether.
A buyer may choose to move forward without requesting work, especially if the home is otherwise a strong fit. Another buyer may request a mitigation credit, ask for a longer-term test, or plan to install a system after closing. The right choice depends on the transaction, the buyer’s comfort level, the home design, and the local market.
At or Above 4.0 pCi/L
A result of 4.0 pCi/L or higher calls for action. In the example above, 4.6 pCi/L exceeds the EPA action level. In many transactions, the buyer requests that the seller install a radon mitigation system before closing, provide a credit, or agree to another solution acceptable to both parties.
A professionally installed mitigation system commonly uses a fan and piping to draw radon gas from beneath the home and discharge it safely above the roofline. The exact design depends on the foundation, slab, crawlspace, sump configuration, and other site conditions. After installation, a follow-up test should confirm that the system is reducing the radon level.
Higher Results, Such as 10.0 pCi/L or More
A high result does not require panic, but it should move quickly from a discussion item to an action item. A reading of 12.3 pCi/L, for example, indicates a substantial radon concentration during the test. Buyers should speak with qualified professionals about mitigation and make sure post-mitigation testing is part of the plan.
Even very high results can often be reduced effectively. The key is not to treat the number as a cosmetic inspection finding. It is an indoor air quality concern that should be addressed with a properly designed system and verified results.
Why the Test Setup Matters
The quality of a radon result depends on more than the device. A report should identify where the monitor was placed, how long the test ran, and whether required closed-house conditions were maintained.
For a real estate transaction, short-term tests typically run for at least 48 hours. During that period, windows should remain closed except for normal entry and exit. Exterior doors should stay closed as much as practical, and whole-house fans or open-window ventilation should not be used. These conditions help prevent outside air from artificially lowering the result.
The device is placed in the lowest level that could be regularly occupied, whether that is a finished basement, an unfinished basement, or the first floor of a home without a basement. It should not sit in a kitchen, bathroom, laundry area, crawlspace, or near drafts, heat sources, or high humidity.
A dependable report also documents quality-control information. Continuous monitors can record whether the device was moved or disturbed. If test conditions were not met, the proper answer may be retesting rather than relying on a questionable number.
A Radon Test Result Is Specific to That Home
One of the most common misconceptions is that a neighbor’s low radon reading proves the next-door home is low too. It does not. Houses on the same street can produce very different radon levels because of differences in foundation type, cracks, drainage, soil contact, and air pressure inside the home.
The same home can also test differently at different times of year. A short-term test is a useful snapshot for a purchase decision, while a long-term test provides a broader average over months. If a short-term result is close to 4.0 pCi/L and there is no immediate closing deadline, a longer test may offer additional perspective. In a fast-moving transaction, buyers and sellers often use the short-term result to reach a practical agreement.
What Buyers, Sellers, and Landlords Can Do Next
For buyers, the report should be reviewed alongside the home inspection findings and contract timeline. If the result is elevated, ask for documentation of the proposed mitigation work, the installer’s qualifications, and post-installation test results. A mitigation system is not a substitute for verification.
For sellers, an elevated result is often easier to manage when addressed directly. Obtaining a mitigation estimate early can reduce uncertainty and help keep negotiations focused. A completed system with a successful follow-up test may also give future buyers confidence.
For landlords and property managers, radon testing can be a sensible part of managing indoor air quality, especially when lower levels are occupied or remodeled. Testing before a space changes use gives you clearer information before tenants move in.
InSpec Home Inspections Maryland provides radon testing as part of a practical, well-documented inspection process. The goal is not to overwhelm you with a number. It is to provide a clear result you can use to make an informed decision.
When to Retest
Retesting is worthwhile after a mitigation system is installed, after major foundation or HVAC changes, or when a lower level becomes a bedroom, office, or family room. Retesting every few years is also a reasonable way to monitor changing conditions in a home.
If your report shows a result near the action level, do not focus only on whether it falls just above or below 4.0 pCi/L. Consider how the home will be used, whether young children or long-term occupants will spend time in the lower level, and whether mitigation would provide useful peace of mind. A clear test report gives you the information to ask the right questions and choose the next step with confidence.
