Here is a question most sellers never think to ask: how does a home built entirely to Minnesota's radon code still test above the EPA's action level?
It happens more often than the code's name suggests. Minnesota has required new homes to include radon-resistant construction since June 2009, and the language sounds like a guarantee. It isn't. The passive systems built into that construction reduce radon by roughly half at best, which means a good number of Eagan homes built in the last seventeen years still carry elevated readings behind a label that implies otherwise. If you're getting ready to list, or you're a buyer who assumed "newer construction" meant "no radon problem," that gap between the label and the actual number is worth understanding before it shows up in a home inspection report and stalls your closing.
The number that actually matters here
Eagan takes this seriously enough that the City of Eagan maintains its own radon page, which tells you something about how common the issue is locally. The city cites a figure from Dakota County testing: roughly 40 percent of radon tests in Dakota County homes come back above the EPA's action level of 4.0 pCi/L. That's not a rare-defect number. That's closer to a coin flip.
Dakota County Public Health backs this with cheap, accessible testing. County residents can buy a test kit for $10 through the department, and staff recommend testing during colder months, when a home's heating system tends to draw more soil gas upward and readings run higher. For a seller trying to get ahead of a problem before a buyer's inspector finds it, that's a low-cost way to know where you stand months before you list.
The two-tier housing stock nobody mentions
Here's the part that gets lost in most radon articles: Eagan's housing stock splits into two very different risk profiles, and neither one is automatically safe.
Homes built before June 2009 have no radon infrastructure at all. No vent pipe, no sealed penetrations, nothing. If radon is entering, it's entering freely, and a mitigation system means a full retrofit.
Homes built after June 2009 are required to have passive radon-resistant construction under the state building code. That means a vent pipe running from below the foundation through the roof, sealed openings around slab penetrations, and a marked electrical junction box in the attic in case a fan needs to be added later. It sounds thorough, and it is a meaningful head start. But the system has no fan. It relies on the natural draw of a home's stack effect to move soil gas up and out, and by itself it typically cuts radon levels by around half, not to zero. A home that started at 8 pCi/L before construction might land around 4 pCi/L with the passive system alone, which is right at the EPA's action level, not comfortably below it.
| Pre-2009 construction | Post-2009 construction | |
|---|---|---|
| Radon infrastructure | None required | Passive vent pipe and sealed penetrations required by code |
| Typical reduction from the system alone | 0 percent | Roughly 50 percent at best |
| Upgrade path if levels are elevated | Full mitigation system installed from scratch | Fan added to existing passive pipe, often a simpler job |
| Assumption buyers tend to make | "Older home, probably has a radon issue" | "New construction, must be fine" |
| Reality | Sometimes true, always worth testing | Often not fine, still worth testing |
The mistake buyers and sellers both make is treating the post-2009 column as a finished answer instead of a head start. It's infrastructure built for a future upgrade, not a completed fix.
What Minnesota disclosure law actually asks for
The state doesn't require you to test your home before selling it. It requires you to tell the truth about what you already know. Under Minnesota's Radon Awareness Act, codified in state statute, a seller must disclose in writing, before the buyer signs a purchase agreement, whether any radon test has occurred, the most current results if one has, and a description of any mitigation or remediation already performed. Sellers also have to hand buyers a copy of the Minnesota Department of Health's publication on radon in real estate transactions, along with a required warning statement about radon exposure.
The liability is what makes this worth taking seriously rather than treating as paperwork. A seller who knows about elevated radon and fails to disclose it is liable to the buyer, who has two years from closing to bring a civil action. That's a long tail for a problem that a $10 test kit or a licensed professional's report could have surfaced before the home ever went on the market.
Worth noting for Eagan sellers specifically: unlike Minneapolis, St. Paul, South St. Paul, Hopkins, and Richfield, Eagan does not require a Truth-in-Housing inspection before a sale. There's no city-mandated point-of-sale evaluation that might catch a radon issue on your behalf. In Eagan, radon awareness is entirely on the seller and buyer to arrange, which is exactly why proactive testing carries more weight here than in a TISH city where an inspector's report becomes part of the file automatically.
The testing itself has rules, and they eat into your timeline
If a buyer requests a radon test during their inspection period, it isn't as simple as leaving a monitor running for a day. Real estate transaction testing requires closed-house conditions, meaning all windows and exterior doors stay shut except for normal entry and exit, for a minimum of 48 hours while the test runs. The test needs to happen on the lowest livable level of the home, typically the basement, and Minnesota requires that anyone performing a radon test in a home they don't own be licensed by the Department of Health. A general home inspector's certification isn't automatically sufficient. That's a scheduling and logistics detail that catches people off guard mid-transaction, especially in a market where inspection periods are already tight.
What mitigation actually costs, if it comes to that
If a test does come back elevated, the fix is usually less dramatic than sellers fear. The Minnesota Department of Health puts typical mitigation system costs in the range of $1,500 to $3,000, installed by a licensed professional. For a home that already has the post-2009 passive infrastructure, the job is often simpler and cheaper, since the vent pipe and sealed penetrations are already in place and the contractor is essentially adding a fan rather than building a system from scratch. Once installed, a mitigation system is inexpensive to run. The Department of Health estimates the electricity cost at a little over $14 a year, a fraction of what it costs to run a home computer.
A short checklist for sellers thinking ahead
- Order a test kit through Dakota County or a licensed measurement professional before you list, especially if your home predates 2009
- If your home was built after 2009, don't assume the passive system means you're in the clear. Test anyway
- Keep any past test results and mitigation paperwork organized. You're required to disclose what you know, and organized records make that easier
- If a buyer's inspection turns up an elevated reading, know that adding a fan to an existing passive system is typically a smaller job than starting from zero
- Budget conversations around a $1,500 to $3,000 range if mitigation becomes part of the negotiation, not a five-figure surprise
Frequently asked questions
Do I have to test my Eagan home for radon before I sell it? No. Minnesota law requires disclosure of what you know, not that you test in advance. But if you don't know your levels and a buyer's inspection turns up an elevated result late in the process, you lose the ability to negotiate mitigation costs into your asking price ahead of time.
My home was built after 2009 and already has the required passive system. Do I still need to test? Yes. The passive system reduces radon by roughly half at best. A home that would have tested high before construction can still test near or above the EPA's action level with the passive system in place. The infrastructure is a head start toward mitigation, not a substitute for it.
Does Eagan require a Truth-in-Housing inspection like Minneapolis does? No. Eagan isn't one of the Minnesota cities with a mandatory point-of-sale inspection ordinance. That means radon awareness in an Eagan transaction depends entirely on what the seller discloses and what the buyer chooses to test for, with no city-run inspection filling the gap.
If you're weighing whether to test before you list, or you want a read on how a radon disclosure might affect your timeline and your net proceeds, Steve Pemberton has spent decades helping Twin Cities sellers get ahead of exactly this kind of question before it becomes a closing-table surprise. What's my home worth, and what should I fix first? That's a conversation worth having early.
