Minnesota law requires a seller to disclose radon information before a purchase agreement is signed. It does not require a test. That gap is where most transactions get complicated — and it is why buyers, sellers, and agents all need to understand the timeline before the clock starts.
A radon test inside a real estate transaction is a different job than a homeowner test. The result goes into a negotiation, both sides have to be able to trust the number, and it has to be finished before a contingency deadline that does not move. That means a documented placement, a controlled closed-house period, tamper detection, and a report you can hand to the other side.
The stakes in Duluth are not theoretical. Minnesota's statewide average indoor radon level is about 4 pCi/L — more than three times the national average of 1.3 — and two out of every five Minnesota homes tested come back at levels the Department of Health considers a major health risk. Duluth sits on the Duluth Complex, fractured gabbro and basalt bedrock under thin glacial soil, with a housing stock full of hillside walkouts, hollow-block foundations, and open sump pits. A high reading here is normal, not exotic.
The single most important thing to know: the Minnesota Radon Awareness Act requires disclosure, not testing. Whether a radon test happens in your transaction is negotiated between buyer and seller. The Minnesota Department of Health strongly recommends that every buyer test before purchase. If you need a test that fits an inspection window, call (218) 520-9679.
Minn. Stat. 144.496 applies to residential real property sales in Minnesota. Before a purchase agreement is signed, the seller must provide the buyer with a written disclosure that includes:
The Radon Warning Statement is standardized language. In substance it tells the buyer that the property may present exposure to dangerous levels of indoor radon gas, that radon is a Class A human carcinogen and the leading cause of lung cancer in nonsmokers and the second leading cause overall, and that the buyer is advised to obtain a radon test before purchase. It also notes that a mitigation system may reduce the risk.
Notice what is absent from that list. There is no requirement that the seller test, no requirement that the buyer test, and no threshold at which a sale is blocked. A seller who has never tested discloses exactly that and has satisfied the statute. This page describes how the law generally works and how deals in this market are customarily handled — it is not legal advice, and questions about your specific contract belong with your agent or attorney.
Your leverage is the inspection contingency window. Once it expires, a radon result is information you have to live with rather than something you can act on. Order the test at the same time you order the home inspection, not after you have read the inspection report.
A short-term transaction test runs a minimum of 48 hours, and it must be preceded by a 12-hour closed-house period before the measurement even begins. Windows and exterior doors stay shut except for normal entry and exit, and whole-house fans stay off. Practically, that means the device is placed, the house is closed up, and you are looking at roughly three days from placement to a usable number, plus turnaround on the report.
Do not use a hardware-store kit for a transaction. It has no chain of custody, so the other side has no way to verify who placed it, where, or under what conditions. It has no tamper detection, so a window opened on day one is invisible in the result. And it goes to a lab by mail, which can add a week you do not have. A continuous radon monitor placed by a licensed measurement professional logs hourly readings, records temperature, humidity, and movement, and produces a dated report with the device serial number on it. That is the document that holds up when a seller pushes back on the number.
If the result comes back at or above the EPA action level of 4.0 pCi/L, mitigation is usually handled one of three customary ways: the seller installs a system before closing, the seller issues a credit at closing and the buyer arranges the work afterward, or the parties adjust the purchase price. None of these is required by law. Which one you get depends on the market, the size of the number, and how much time is left. Our radon mitigation page covers what a system for a given foundation type actually costs, which is the figure you want in hand before you ask for anything.
The worst possible time to learn your house reads 9 pCi/L is nine days into a purchase agreement. At that point you have no leverage, no time to shop installers, and a buyer who is entitled to walk. A test in the month before you list costs you almost nothing and converts a possible crisis into a line item.
If a pre-listing test comes back low, you disclose a clean, documented result and the subject closes itself. If it comes back high, you mitigate on your own schedule, gather quotes instead of accepting the first one, and disclose a permitted, labeled system with a post-installation confirmation test attached. A documented system is a selling point in this market, not a red flag — it tells a buyer the issue was found and permanently resolved. See our radon testing page for how seasonal timing affects the number you will get.
Placement to written report is typically three to four business days on a short-term transaction test: 12-hour closed-house period, 48-hour measurement, then same-day or next-day reporting from a continuous monitor. Build that into the contingency period rather than discovering it on day twelve.
One compliance note worth repeating to clients: Minnesota law requires MDH licensure for anyone performing radon testing or mitigation in a building they do not own or lease. National industry certification alone is not sufficient in Minnesota. A buyer cannot place a kit in a seller's home and call it a professional measurement, and an unlicensed tester's report is a weak foundation for a price negotiation. Encouraging a pre-listing test protects everyone in the transaction — it removes the surprise, removes the deadline pressure, and removes the argument about whose number is right.
These are customary outcomes in this market, not rules. Every deal is negotiated on its own terms.
| Result | Status | What typically happens |
|---|---|---|
| Under 2.0 pCi/L | Below EPA's advisory range | Disclosed and closed. No action requested in most deals. Retest every two years or after major foundation work. |
| 2.0–3.9 pCi/L | EPA suggests considering mitigation | Usually disclosed without a demand, though some buyers ask for a credit. A winter reading in this band often crosses 4.0 in a colder month. |
| 4.0–7.9 pCi/L | At or above the EPA action level | Mitigation is commonly requested. Seller installs before closing, credits at closing, or the price is adjusted. |
| 8.0 pCi/L and up | Well above the action level | Mitigation is almost always negotiated, frequently with the seller installing before closing plus a confirmation test as a condition. |
A radon test measures the house under closed conditions. Open a basement window for a day and you dilute the air the device is sampling, and the average comes back artificially low. That is not a small effect — it can move a result from 6 pCi/L to under 3.
Whether the cause is an occupant airing out the house, a contractor propping a door, or something less innocent, the outcome is the same: the number is wrong and both parties are making decisions on bad data. A continuous monitor is designed to catch it. Hourly readings show the telltale collapse and recovery of a ventilation event, and onboard sensors log temperature, humidity, barometric pressure, and physical movement of the device. If the conditions were violated, the report says so and the test gets repeated. A passive kit cannot tell you any of this, which is the core reason it does not belong in a transaction. Questions about a specific property or timeline? Send us the details and we will tell you what fits your window.
Yes. The Minnesota Radon Awareness Act requires disclosure, not testing, so a seller is not legally obligated to allow a radon test. In practice, refusing access is uncommon and tends to raise more questions than it answers. Whether testing happens is a term of the purchase agreement like any other, negotiated between the parties. If you are a buyer, write the radon test into the inspection contingency rather than assuming access. If a seller does refuse, that is information worth weighing before you release your contingency.
There is no legal answer — it is negotiated. In Duluth transactions, three outcomes are customary when a result comes back at or above 4.0 pCi/L: the seller installs a system before closing, the seller credits the buyer at closing and the buyer arranges the work, or the purchase price is adjusted by roughly the cost of the system. Which one you get depends on the market, the size of the reading, and remaining time. Get a real mitigation quote before you negotiate, because most Minnesota systems land between $1,500 and $3,000.
Generally no, and it often helps. A documented system with an electrical permit, a permanent installer label, a working manometer, and a post-installation confirmation test tells a buyer that a known regional problem was identified and permanently fixed. What causes trouble at resale is an undocumented system — a fan and a pipe with no paperwork, no permit, and no proof it ever lowered the number. Keep the install records, the permit, and the confirmation test result together, because Minnesota's disclosure law asks about mitigation system operation and maintenance.
Plan on three to four business days from placement to written report. The measurement itself runs a minimum of 48 hours, but it has to be preceded by a 12-hour closed-house period, and a report follows. A continuous monitor reports quickly because the data is read off the device rather than mailed to a lab. A charcoal kit sent through the mail can add a week or more, which is the main reason it is a poor fit for an inspection contingency with a fixed deadline.
You can, but it is a weak instrument in a negotiation. A store kit has no chain of custody, so nobody can verify who placed it, where it sat, or whether the house stayed closed. It has no tamper detection, so a window opened during the test is invisible in the result. And lab turnaround by mail is slow. Minnesota also requires MDH licensure for anyone testing a building they do not own or lease, so a buyer cannot place a kit in a seller's home and present it as a professional measurement.
It depends on where you are in the contract. If the inspection contingency is still open, you have room to request mitigation, a credit, or a price adjustment. If it has expired, your options narrow considerably. This is the argument for ordering the radon test on day one alongside the home inspection instead of waiting for the inspector's report. A system installs in about a day, but permitting, scheduling, and the 24-hour wait before a confirmation test mean it is not something you can compress into 48 hours.
The Minnesota Department of Health recommends testing, and there is a practical case for doing it before you list. A pre-listing test gives you time to gather quotes, choose an installer, and disclose a finished, permitted system rather than negotiating under a deadline with a buyer who can walk. If the result is low, you have clean documentation for the disclosure. Testing during the heating season gives you the more conservative number, since Duluth's long winters run the stack effect for much of the year.
Tell us the property and your contingency date and we will tell you whether a 48-hour test fits the window — and what the result would likely mean at the table.