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County-by-county data, what to tell clients, when to recommend testing, and how radon affects your transactions.
Radon is a naturally occurring radioactive gas that forms from the decay of uranium in soil and rock. It seeps into homes through cracks in the foundation, gaps around pipes, sump pits, and any opening where the house meets the ground. It's colorless, odorless, and tasteless — impossible to detect without testing.
The health risk is significant. Radon is the leading cause of lung cancer among non-smokers and the second leading cause overall, behind smoking. The EPA estimates radon causes approximately 21,000 lung cancer deaths annually in the United States. The risk increases with concentration level and duration of exposure.
Michigan is divided into three EPA radon zones. Most of Southeast Michigan falls in Zone 2 (moderate risk), with some areas in Zone 1 (highest risk). Here's what the data shows for the counties where most of your transactions happen:
Washtenaw, Livingston, and Lapeer Counties generally show higher risk than the tri-county area, falling into EPA Zone 1. If you work in those markets, radon testing is even more critical.
Radon is measured in picocuries per liter (pCi/L). The EPA has established clear action levels, but understanding the nuance helps you advise clients more effectively:
Below the national average of 1.3 pCi/L for indoor air. No action needed. This is a positive finding to share with buyers.
Below the EPA action level but above average. The EPA suggests considering mitigation. There is no known safe level of radon. Some buyers choose to mitigate at this range for peace of mind.
The EPA recommends mitigation at or above 4.0 pCi/L. This does not mean the home is dangerous to enter — it means long-term exposure at this level increases lung cancer risk and a mitigation system should be installed.
Radon can alarm buyers unnecessarily if not framed properly. Here's how experienced agents handle the conversation:
"Radon testing is standard in Michigan. About 1 in 4 homes test above the action level. If it comes back high, it's fixable — not a deal-breaker."
"Great news — the home tested well below the EPA action level. One less thing to worry about."
"The radon level came back above 4 pCi/L, which means the EPA recommends a mitigation system. The good news: these systems are very effective and we can negotiate the installation as part of the transaction."
"This doesn't mean the home is unsafe to enter or live in short-term. Radon risk is about long-term exposure over years. A mitigation system brings levels down dramatically — typically below 2 pCi/L — and can be installed in a day or two."
If radon testing reveals elevated levels, the fix is straightforward and effective. Understanding the basics helps you keep deals on track when clients hear "radon" and get nervous.
Elevated radon rarely kills a transaction. It's one of the most negotiable inspection findings because the fix is well-understood, effective, and relatively affordable. Here's how it typically plays out:
Understanding the testing process helps you set expectations with clients and avoid scheduling confusion:
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Located in Troy Michigan, we inspect homes and commercial buildings in the following counties:
Please call us even if you are outside the area. We will make an effort to accommodate you, and your house inspection needs.