When you should test
- You've never tested. Most Flint-area homes haven't, and this housing stock is exactly the kind that runs high.
- You're buying or selling. Radon is now a standard line item in Genesee County home inspections, and our real estate radon page covers the deal mechanics.
- It's been two years since your last test, or since your mitigation system went in.
- You've finished the basement, changed the HVAC, or added on. Anything that changes how air moves through the house can change the number.
Best season to test: winter, closed-house conditions. That's when levels peak and when the number reflects your real worst case. A summer test that comes back moderate deserves a winter follow-up before you relax.
- Lowest lived-in level
- Away from the sump, drafts, kitchen and bath
- Closed-house conditions, 48 hours
Short-term vs. long-term
Short-term tests run 48 hours to about a week under closed-house conditions and are the standard for real estate deadlines and first looks. Long-term tests run 90 days or more and capture your true average across seasons, the better answer when nobody's rushing you. A sensible pattern for a homeowner with no deadline: short-term first; if it's borderline, follow with a long-term.
Reading your result
| Result | What it means |
|---|---|
| Under 2.0 pCi/L | Good. Retest every two years and after any major change to the house. |
| 2.0-3.9 pCi/L | The gray zone. The EPA says consider fixing. There's no fully safe level, and homes in this band often cross 4.0 in winter. Worth a conversation, not a panic. |
| 4.0+ pCi/L | The EPA action level. Fix the home. This is a solved problem: see the installation page, and in most houses it's solved in a day. |
Free and low-cost testing, because we'd rather you test than not
The Michigan Indoor Radon Program runs a hotline at 800-723-6642, and the Genesee County Health Department offers radon test kits year-round from its Environmental Health division at 630 S. Saginaw St. in Flint, free during Radon Action Month events and low-cost the rest of the year. Call (810) 257-3603 to check current availability. If budget is the thing standing between you and a number, use the state's kit. Then, if the number's high, call us. We'd genuinely rather lose the testing fee than have a Flint family not know.
If it comes back high
Don't retest five more times hoping for a different answer, and don't start pricing air purifiers. Filters don't touch radon. A confirmed high result means the soil under your house is the source and depressurization is the fix. Send us the number and a couple basement photos, and you'll have a firm quote and an install date before the week is out.
Frequently asked
How long does a radon test take?
A minimum of 48 hours for a short-term test, with windows and doors kept closed apart from normal coming and going. Real-estate transactions almost always use the 48-hour protocol.
Can I just buy a kit and test myself?
Yes, and a properly used kit is a legitimate first look. Follow the closed-house rules, put it in the lowest lived-in level, keep it away from drafts and the sump, and mail it promptly. For real estate deals, use a professional test. Buyers and lenders will want the chain of custody.
What's a safe level of radon?
There isn't one, strictly speaking. Risk scales with exposure at every level. The working standards: 4.0 pCi/L is the EPA's fix-it line, and below 2.0 is where mitigation systems like ours are designed to land.
Do radon levels really change with the seasons?
Substantially. Frozen ground and closed windows push Michigan winter readings well above summer readings in the same house. It's why a marginal summer number gets a winter retest.