What to Do If Your Radon Test Comes Back High

You tested your home, the results came back, and the number is higher than 4.0 pCi/L. If your first reaction was a jolt of worry, that is a normal response — but this is a fixable problem, and you have more time than the moment probably feels like you do.

Elevated radon is common across Onondaga County. The entire county sits in EPA Radon Zone 1, the agency’s highest-risk classification, which means the predicted average indoor screening level here is above the action level. A high result does not mean your house is defective or that you did something wrong. It means your home sits on the same Central New York geology as everyone else’s, and now you know your number.

First: Understand What the Number Means

Radon is measured in picocuries per liter of air, abbreviated pCi/L. The EPA recommends taking action at or above 4.0 pCi/L, and suggests homeowners consider action between 2.0 and 4.0 pCi/L as well.

That 4.0 threshold is a policy guideline, not a cliff edge. There is no level of radon considered completely risk-free, and the risk rises as the concentration rises. A home at 4.5 pCi/L and a home at 30 pCi/L are both above the action level, but they are not equivalent situations. The higher your reading, the more urgency it deserves.

Some rough context for interpreting your result:

• 2.0–4.0 pCi/L — below the action level, but reduction is worth considering, particularly if anyone spends significant time in the basement.
• 4.0–10 pCi/L — the most common range for elevated Central New York homes. Mitigation is recommended.
• 10–20 pCi/L — meaningfully elevated. Move on this rather than sitting on it.
• Above 20 pCi/L — high. Prioritize getting a system installed, and in the meantime limit time spent in the lowest level of the home.

Second: Consider Whether to Confirm the Result

Whether you should retest depends on how you got your number in the first place.

If your result came from a professional short-term test using a continuous radon monitor under proper closed-house conditions, that reading is reliable enough to act on. Continuous monitors log hourly readings, flag tampering, and account for conditions during the test.

If your result came from a hardware-store charcoal kit, a confirmation test is worth considering — especially if your reading landed close to the action level. Passive kits are useful screening tools, but they are sensitive to placement, humidity, and how promptly the kit reached the lab. A kit reading of 4.3 pCi/L might warrant a second look. A kit reading of 18 pCi/L does not; that home has a radon problem regardless of the margin of error.

One exception worth knowing: if you are in the middle of a real estate transaction, the testing protocol matters and the timeline is usually short. In that situation, professional radon testing with documented results is what buyers, sellers, and agents will expect.

Third: Understand What the Fix Involves

Here is the part that surprises most homeowners: radon reduction is a routine, well-established job with a very high success rate. This is not an open-ended remediation project with an unpredictable outcome.

The standard approach for a home with a basement or slab is active sub-slab depressurization. A pipe is installed through the foundation floor into the gravel or soil beneath it. A continuously running fan draws radon-laden air from under the slab and vents it above the roofline, where it disperses harmlessly. Because the system maintains lower pressure beneath the slab than inside the house, radon is pulled out rather than being drawn up through cracks and openings.

Most residential systems are installed in a single day. The fan uses a modest amount of electricity and typically runs for many years before it needs replacement. Sealing visible foundation cracks and sump openings is usually part of the work, improving system performance.

For homes with crawl spaces, the approach differs somewhat — typically a sealed membrane over the crawl space floor with suction drawn from beneath it — but the operating principle is identical.

Fourth: Know Roughly What It Costs

Most Syracuse-area radon mitigation systems depend on foundation type, home size, and system complexity, depending on foundation type, home size, and how complex the routing needs to be. A straightforward full basement with an accessible interior route tends toward the lower end. Multiple foundation types, a finished basement that constrains where pipe can run, or a home requiring more than one suction point pushes the number up.

Get a clear estimate before any work begins. A reputable contractor will look at your foundation, explain where the system will run, and give you a number in advance rather than a vague range.

Fifth: Insist on a Post-Mitigation Retest

This step matters and is sometimes skipped. After installation, your home should be retested to confirm the system actually brought levels down below the action level.

A retest is the only proof the work succeeded. It also gives you documentation, which becomes useful if you sell the home later — New York addresses radon on the Property Condition Disclosure Statement, and being able to show a high initial reading, a professionally installed system, and a low follow-up reading turns a potential negotiating problem into a selling point.

What You Should Not Do

Do not panic-sell or panic-renovate. Radon risk accumulates over years of exposure. A few weeks between discovering elevated levels and installing a system is not a crisis.

Do not rely on ventilation alone as a permanent fix. Opening basement windows can temporarily lower readings, but it is not a solution — it fails in a Syracuse winter, it wastes energy, and it depends on someone remembering to do it.

Do not assume sealing cracks will be enough. Sealing helps a mitigation system work better, but on its own it rarely brings elevated levels down to a safe range. Soil gas will find another path.

Do not ignore it because the number is only slightly above 4.0. The action level is a guideline, not a safety line. Reduction is still worthwhile at 4.5 pCi/L.

A Realistic Timeline

For most Onondaga County homeowners the sequence looks like this: confirm the result if your original test was a passive kit, get one or two estimates from certified contractors, schedule installation, have the system installed in a day, then retest to confirm. Start to finish, that is typically a matter of weeks, not months — faster when a real estate closing is driving the schedule.

Radon is the second leading cause of lung cancer in the United States and the leading cause among people who have never smoked. It is also one of the few household health risks with a definitive, permanent, affordable fix. You found the problem. The rest is straightforward.

Serving Syracuse, Cicero, Liverpool, Baldwinsville, Camillus, Manlius, DeWitt, and the surrounding Onondaga County communities. Call (315) 234-2853 for certified testing, mitigation, and a free estimate.

Elevated results are common throughout the county, including Liverpool and the city of Syracuse itself, and a high number is a solvable problem rather than a defect in your home.