What Are Safe Radon Levels in a Home — and When Should You Act?

What a Radon Reading Actually Tells You

When you get a radon test result back, it comes as a number measured in picocuries per liter — written as pCi/L. That unit sounds technical, but it simply describes the concentration of radon gas present in a given volume of air inside your home. Think of it as a density reading: the higher the number, the more radon is present, and the more consistently you and your family are breathing it in over time. A result of 1.0 pCi/L, for example, is roughly in line with the average outdoor air level in the United States. A result of 8.0 pCi/L means the concentration inside your home is meaningfully elevated — and that distinction matters for your long-term health.

Radon itself is a naturally occurring radioactive gas that forms when uranium in soil and rock breaks down. It seeps up through the ground and can accumulate in any home — new or old, well-sealed or drafty. In Kannapolis, Concord, and Landis, and the surrounding Piedmont region, the underlying geology creates conditions where elevated radon levels are more common than many homeowners expect. That's not a reason for alarm, but it is a reason to know your number.

The EPA Action Level — and What It Means in Practice

The U.S. Environmental Protection Agency has established 4.0 pCi/L as the action level for residential radon. At or above that threshold, the EPA recommends taking steps to reduce radon concentrations in your home. This isn't an arbitrary line — it reflects decades of research on lung cancer risk associated with long-term radon exposure. The EPA also notes that levels between 2.0 and 4.0 pCi/L fall into a range where mitigation is worth considering, particularly if you spend significant time in lower levels of your home like a finished basement or a ground-floor bedroom.

To put those numbers in everyday context: the national average indoor radon level is about 1.3 pCi/L. A home testing at 4.0 pCi/L has roughly three times that concentration. A home at 8.0 pCi/L has about six times the average. Radon mitigation systems — typically a sub-slab depressurization system installed by a certified contractor — are effective at bringing elevated levels down, often to below 2.0 pCi/L. The test result is simply information. It tells you where you stand so you can decide what, if anything, to do next.

EPA and WHO Radon Level Reference Table

The EPA and the World Health Organization use different reference points, though both are grounded in the same body of epidemiological research. The table below summarizes how each agency classifies radon concentration levels and what action they recommend at each range.

Level (pCi/L)	EPA Classification	WHO Guidance	Recommended Action
Below 2.0	Low risk	Below reference level	No action required
2.0 – 2.7	Consideration range begins	At or above WHO reference level	WHO recommends mitigation; EPA monitoring
2.7 – 4.0	EPA consideration range	Above WHO reference level	Consider mitigation, especially if children present
4.0 and above	EPA action level	Well above WHO reference level	Both agencies: mitigate

The WHO's reference level — 2.7 pCi/L (or 100 Bq/m³ in the unit European regulators use) — is lower than the EPA's action level. This difference does not mean the two agencies disagree; it reflects differing regulatory philosophies and the populations they were designed to address. The EPA's 4.0 pCi/L threshold was set as a practical action level — a point at which mitigation is clearly warranted and clearly cost-effective. The WHO's lower reference level reflects a precautionary approach that accounts for the cumulative risk at moderate exposures over a lifetime.

For Kannapolis, Concord, and Landis homeowners, the practical implication is straightforward: a result below 2.0 pCi/L is genuinely low by any standard. A result between 2.0 and 4.0 pCi/L falls in a range where the decision to mitigate is reasonable, particularly if children live in the home or if lower levels are regularly occupied. A result at or above 4.0 pCi/L triggers the EPA's recommendation to act.

North Carolina Context: Why Kannapolis, Concord, and Landis Results Matter

Radon levels across North Carolina are not uniform. The state's coastal plain, with its sandy, porous soils, tends to produce lower indoor radon levels than the Piedmont and mountain regions. Kannapolis, Concord, and Landis sit in the Piedmont — underlain by the Carolina Slate Belt and older crystalline rock formations that contain elevated concentrations of uranium and radium, the parent materials that produce radon. The North Carolina Department of Health and Human Services has identified the Piedmont as a region where elevated indoor radon is more likely than in coastal areas.

This does not mean every home in Kannapolis or Concord has elevated radon. It means the geological conditions that produce radon are more prevalent here than in other parts of the state, and that a test — rather than an assumption — is the only meaningful way to know where any individual home stands. Two homes on the same street, built the same year with the same floor plan, can produce meaningfully different test results because soil conditions, foundation crack geometry, and home pressure dynamics vary property by property.

What the regional context does tell you is that testing in Kannapolis, Concord, and Landis is a locally grounded decision, not a borrowed precaution from somewhere else. The geology of this region creates real conditions that produce real radon. Whether your result is low or elevated, knowing your number is the starting point for any informed decision about your family's indoor air quality.

How to Read Your Own Results With Confidence

If your test comes back below 2.0 pCi/L, you can feel genuinely reassured. That result is consistent with low-risk indoor air quality, and no action is required. If your result falls between 2.0 and 3.9 pCi/L, you're in a range where a conversation with a radon professional is worthwhile — especially if you're planning to sell the home, if children live there, or if you spend a lot of time on the lowest level. At 4.0 pCi/L or above, the EPA's guidance is clear: act. That doesn't mean panic — it means scheduling a mitigation consultation and moving forward with a straightforward fix that most contractors can complete in a single day.

One important note: a single short-term test gives you a useful snapshot, but conditions in a home can vary with seasons, weather, and how tightly the house is closed up. A professionally conducted test using calibrated equipment — placed correctly and retrieved under controlled conditions — gives you a result you can actually rely on. That's the difference between a number that leaves you guessing and one that gives you a clear, confident path forward.

Getting a Test You Can Trust in Kannapolis, Concord & Landis

If you're a homeowner in Kannapolis, Concord, or Landis and you haven't tested for radon — or if it's been several years since your last test — a professional residential radon test is the most straightforward way to know where you stand. Professional testing uses certified and professionally calibrated equipment and gives you a result that holds up whether you're making a personal health decision or preparing for a real estate transaction.

You don't need to interpret the results alone. When your test is complete, you'll have a clear number, a plain-language explanation of what it means, and a straightforward recommendation for next steps — whether that's peace of mind or a referral to a qualified mitigation contractor. Knowing your radon level is one of the simplest, most concrete things you can do for the long-term health of everyone in your home.