How to Test for and Mitigate Radon in Minnesota: Complete Guide

How to Test for and Mitigate Radon in Your Minnesota Home

Minnesota has one of the highest radon exposure rates in the country. Over 40% of homes statewide test above the EPA’s action level of 4 picocuries per liter (pCi/L), and in some counties, that number exceeds 60%. Radon is the leading cause of lung cancer among non-smokers, responsible for an estimated 21,000 deaths annually in the United States. In Minnesota, the combination of uranium-bearing glacial till soil and tightly sealed homes creates conditions that concentrate radon to dangerous levels.

This guide covers how radon enters Minnesota homes, how to test accurately, how to interpret results, and how to install effective mitigation systems.

What Radon Is and Why Minnesota Has So Much of It

Radon is a naturally occurring radioactive gas produced by the decay of uranium in soil and rock. It’s colorless, odorless, and tasteless—you can’t detect it without a test. Radon enters homes through any opening in contact with the ground: foundation cracks, gaps around plumbing and wiring penetrations, sump pump openings, and porous concrete block walls.

Minnesota’s soil is particularly radon-prone because of its geological history. Glacial deposits left uranium-rich soil and gravel across much of the state. The bedrock formations—particularly the Jordan sandstone and Prairie du Chien dolomite underlying the Twin Cities metro and southeastern Minnesota—contribute to elevated radon levels.

The state’s cold climate compounds the problem. Minnesota homes are sealed tight to conserve energy, which traps radon that might otherwise dissipate. The “stack effect”—warm air rising and exiting through the upper levels—draws radon-laden soil gas into the basement and lower levels. During winter, when homes are sealed tightest and the stack effect is strongest, indoor radon levels can spike 50-100% above summer levels.

Radon Levels by Minnesota Region

The Minnesota Department of Health recommends testing every home, regardless of location or age. Even in areas with lower average levels, individual homes can test much higher depending on local soil conditions, foundation construction, and ventilation patterns.

Step 1: Test Your Home

Testing is simple, inexpensive, and the only way to know your radon level. There are two main approaches:

Short-Term Testing (2-7 Days)

The quickest way to get an initial reading. Short-term tests use either charcoal canisters or continuous radon monitors placed in the lowest livable level of the home (usually the basement).

• DIY test kits: Available at hardware stores or through the Minnesota Department of Health for $5-$15. You place the device, wait 2-7 days, and mail it to a lab. Results arrive in 1-2 weeks.
• Professional testing: A licensed radon measurement professional deploys a continuous radon monitor (CRM) for 48+ hours. Results are immediate when the device is retrieved. Cost: $125-$175. This is the standard for real estate transactions.

Testing conditions: Close all windows and exterior doors 12 hours before and during the test. Normal entry and exit is fine, but don’t leave doors or windows open. Place the test device in the lowest livable level, at least 20 inches above the floor, away from drafts, exterior walls, and sump pits.

Long-Term Testing (90+ Days)

Provides a more accurate annual average because radon levels fluctuate seasonally. Long-term alpha track detectors cost $20-$30 and are left in place for 3-12 months. The Minnesota Department of Health considers long-term tests more reliable for determining actual exposure risk, but they’re impractical during a real estate transaction.

When to Test

• Before buying any Minnesota home (non-negotiable)
• If you’ve never tested your current home
• After finishing a previously unfinished basement
• After major foundation work
• Every 2-5 years for ongoing monitoring, even if previous tests were low
• If you’ve installed new ventilation or made significant changes to the building envelope

Step 2: Interpret Your Results

The EPA action level of 4.0 pCi/L is not a “safe” threshold—it’s a practical action point. The World Health Organization recommends action at 2.7 pCi/L. Any reduction in radon reduces health risk. Mitigation systems typically reduce levels to 1-2 pCi/L regardless of starting point, making them effective even for moderate levels.

Step 3: Install a Mitigation System

Radon mitigation in Minnesota almost always uses Active Soil Depressurization (ASD)—a fan-powered system that draws radon-laden air from beneath the foundation and vents it above the roofline before it enters the home.

How ASD Works

1. A 3-4 inch hole is drilled through the basement floor slab
2. A suction pit is created beneath the slab (roughly 12 inches deep, 18 inches across) to create an air collection space
3. PVC pipe (3 or 4 inch) connects the suction pit to an inline fan
4. The fan creates negative pressure beneath the foundation, pulling radon-laden air into the pipe instead of into the home
5. The pipe routes through the house to the roofline, where radon is vented above the roof (typically on the side or back of the house)
6. The system runs continuously, drawing 20-40 watts of power (similar to a light bulb)

Mitigation Costs

Most Minnesota homes are mitigated for $800-$1,500 total, including installation, materials, and post-mitigation testing. The system is typically installed in one day (4-8 hours). Post-mitigation radon levels usually drop to 1-2 pCi/L—a 70-90% reduction from pre-mitigation levels.

System Routing Options

The PVC pipe from the basement to the roofline can be routed several ways:

• Interior through closet or utility chase: Least visible, preserves exterior appearance. Requires accessible path from basement to attic.
• Exterior along siding: Easier installation, more visible. Common when interior routing isn’t practical. The pipe is painted to match siding.
• Through garage: If the garage shares a foundation wall, routing through the garage to the roof keeps the pipe out of living space.

Step 4: Radon in Real Estate Transactions

For home buyers and sellers in Minnesota, radon is a standard part of the transaction:

For Buyers

• Always test during the inspection period. Don’t skip this—it costs $125-$175 and could reveal a health hazard.
• If levels exceed 4 pCi/L, negotiate mitigation as part of the purchase agreement. Options include requesting the seller install a system before closing, requesting a credit toward mitigation ($800-$1,500), or accepting the condition and installing yourself post-purchase.
• If the seller has a mitigation system already installed, verify it’s functioning (fan running, U-tube manometer showing pressure) and request a current test to confirm effectiveness.
• Minnesota does not legally require radon testing at sale, but it’s strongly recommended and has become standard practice.

For Sellers

• Minnesota law requires sellers to disclose known radon test results on the property disclosure form.
• Proactive testing and mitigation before listing removes radon as a negotiation point. A mitigated system with a test showing levels below 4 pCi/L makes your home more attractive to buyers.
• If you’ve had radon testing done, you must disclose results. Withholding known test results violates Minnesota disclosure law.

Learn more about purchase negotiation strategies in our homebuying guide and estimate full transaction costs with the closing cost calculator.

Step 5: Maintain Your Mitigation System

Mitigation systems are low-maintenance but not zero-maintenance:

• Check the U-tube manometer monthly. This simple device (a small curved tube with colored liquid) is typically installed on the radon pipe in the basement. If the liquid levels are unequal, the fan is creating suction and the system is working. If levels are equal, the fan has failed.
• Listen for the fan. A running fan produces a low hum. Silence means failure. Some systems include an audible alarm.
• Replace the fan every 8-12 years. Radon fans run continuously and eventually wear out. Replacement cost: $150-$300 installed.
• Retest every 2 years. Use a short-term test to verify the system is maintaining levels below 4 pCi/L.
• Keep the exhaust pipe clear. In Minnesota, check that snow hasn’t blocked the exhaust opening at the roofline after heavy snowfall.

Radon-Resistant New Construction (RRNC)

Minnesota building code requires radon-resistant features in new construction in most of the state. These features include a gas-permeable layer (gravel) beneath the foundation slab, a plastic vapor barrier over the gravel, a 3 or 4-inch PVC pipe from below the slab routed through the house to the roof (passive system), and sealed slab cracks and pipe penetrations.

The passive pipe system can be activated by adding a fan ($300-$500) if post-construction testing reveals elevated radon levels. This is significantly cheaper than retrofitting a system in an older home without the pre-installed pipe ($800-$1,500). If you’re buying new construction in Minnesota, verify these RRNC features are included and test after occupancy.

Common Myths About Radon

Finding a Radon Professional in Minnesota

Minnesota requires licensing for radon measurement and mitigation professionals through the Minnesota Department of Health (MDH). Two separate licenses exist: Radon Measurement (testing) and Radon Mitigation (system installation).

Verify any radon professional’s license at the MDH website. Ask specifically about their experience in your area—soil conditions and foundation types vary across the state, and local experience improves system design.

Find contractors through our home services directory, the MDH licensed radon professional list, or the National Radon Proficiency Program (NRPP) directory.

Frequently Asked Questions

How much does radon mitigation cost in Minnesota?

Most residential mitigation systems cost $800-$1,500 installed. Homes with complex foundations (multiple foundation sections, crawl space + slab, etc.) may require multiple suction points, pushing costs to $1,500-$2,500. Activating a passive system in new construction costs $300-$500. Annual operating cost is $30-$60 in electricity. These costs are modest compared to the health risk of long-term radon exposure. Use our mortgage calculator to factor mitigation costs into your home purchase budget.

Does radon affect home value?

Elevated radon levels (with no mitigation) can affect buyer willingness and sale price. However, a professionally installed mitigation system with documented post-test results below 4 pCi/L resolves the concern for most buyers. Mitigation systems are common enough in Minnesota that their presence is normal, not stigmatizing. In practice, a mitigated home sells comparably to a home that never had high radon.

Is radon worse in winter?

Yes. Winter radon levels in Minnesota homes are typically 50-100% higher than summer levels due to sealed windows, the stack effect drawing more soil gas inside, and frozen soil concentrating radon beneath the foundation. The EPA recommends testing in winter for this reason—it captures the worst-case scenario. If your winter test is below 4 pCi/L, you can be confident levels are acceptable year-round.

Can I install a mitigation system myself?

Technically yes, but Minnesota law requires a licensed mitigator to perform work for hire. If you’re doing it yourself for your own home, you can install the system, but you forfeit the professional warranty and may affect the home’s radon disclosure status for future sales. Professional installation ensures proper design, seal quality, and compliance with state guidelines. For $800-$1,500, professional installation is worth the cost and documentation. Explore our affordability calculator to budget for radon mitigation as part of your purchase plan.

Do condo and apartment residents need to worry about radon?

Ground-floor and basement-level units are at risk. Upper-floor units (third floor and above) typically have minimal radon exposure because the gas dissipates as it rises through the building. If you’re buying a ground-floor condo or townhome in Minnesota, test as you would a single-family home. The condo association may be responsible for mitigation of common elements, but testing your individual unit is your responsibility.