You cannot see or smell radon, yet it is the leading environmental cause of lung cancer in the U.S. If you own a home in Manhattan, Montana or you are planning a move, radon should be on your checklist. The good news is testing is simple and mitigation is proven and affordable in most homes. In this guide, you will learn what radon is, why it matters in Gallatin County, how to test, what your results mean, and how to reduce radon during a real estate transaction. Let’s dive in.
What radon is and why Manhattan should care
Radon is a naturally occurring radioactive gas created by the decay of uranium in soil and rock. It moves into homes through cracks, gaps, sump pits, and other openings. Because it is colorless and odorless, you only know your level by testing.
Radon exposure is a health risk that increases with both concentration and time. It is the second-leading cause of lung cancer overall, and smokers face even higher combined risk. That is why every home should be tested.
Much of Montana has elevated radon potential due to local geology. Gallatin County, which includes Manhattan, is commonly identified as an area with notable radon potential. The practical takeaway is simple: assume a non-trivial chance of elevated indoor radon and plan to test every home.
How to test a home in Gallatin County
Testing is straightforward and inexpensive. You can use consumer test kits or hire a professional. Choose your timing and method based on your goals.
When to test
- Sellers: Test pre-listing if time allows. You can address issues early and give buyers confidence.
- Buyers: Test during the inspection contingency with a qualified professional or reputable kit.
- New residents: If no test was done at purchase, test within your first year in the home.
- Seasonal note: Radon varies through the year. Long-term tests that include the heating season are more representative.
Short-term vs long-term tests
- Short-term tests run 2 to 7 days. Charcoal canisters, electret ion chambers, and professional continuous radon monitors are common. These are typical for real estate timelines.
- Long-term tests run 90 days or more. Alpha-track detectors or long-term monitors give a better measure of your annual average.
- Continuous Radon Monitors record hourly values. Professionals often use them for real estate testing to document conditions.
Where and how to place tests
- Place the device on the lowest livable level where you spend time, like a basement or ground floor.
- Follow closed-house conditions as directed. Keep windows and exterior doors closed as much as possible during testing.
- Avoid drafts, appliances, vents, or exterior walls. Follow the device instructions, record start and stop times, and note any unusual events.
- For transaction testing, consider a professional who follows EPA protocols.
Interpreting results
- The EPA recommends action at 4.0 pCi/L or higher.
- Results below 4.0 pCi/L still carry some risk. Many experts consider mitigation above 2.0 pCi/L, especially for smokers or other at-risk occupants.
- If a short-term test is elevated, follow up with a second short-term professional test or a long-term test before or after mitigation, per EPA guidance.
Proven ways to reduce radon
You can reduce radon in most homes with well-established methods. The right approach depends on your foundation and how radon is entering your home.
Most common method: active sub-slab depressurization
Active sub-slab depressurization, often called ASD, is the standard for homes with a basement or slab. A fan and piping draw air from beneath the slab and vent it above the roofline. Properly designed systems often cut radon by 50 to 99 percent and typically bring levels below 4.0 pCi/L, with many homes achieving less than 2.0 pCi/L.
Crawlspaces and sump pits
For crawlspaces, sub-membrane depressurization covers soil with plastic and uses a fan to draw air from beneath the membrane. If a sump pit is a radon entry point, a sealed sump cover can be tied into the mitigation system.
Sealing and ventilation
Sealing cracks and openings helps the system work better, but sealing alone is not enough. In some cases, mechanical ventilation or an HRV or ERV can supplement a mitigation system.
Cost, timing, and what to expect
- Home test kits: about $15 to $50.
- Professional short-term test for a real estate transaction: roughly $100 to $300.
- Mitigation system installation: commonly $800 to $3,000+, depending on home size, foundation type, and complexity.
- Installation time: often one day for typical homes, with more complex projects taking longer.
- Post-installation test: required to confirm the system works as intended. Adjustments may be needed.
Choosing a certified professional
Select a contractor certified by the National Radon Proficiency Program or the National Radon Safety Board, or recognized by the state. Ask for:
- A detailed written plan with a fixed-price estimate
- Proof of certification, insurance, and business license
- References and recent examples
- Clear expectations for reduction and post-mitigation testing
- Warranty details for the fan and workmanship
Check with Gallatin City-County Health and local building departments for any permit or inspection requirements.
Radon during a real estate transaction
Radon does not have to derail your sale or purchase. With a clear plan, you can protect health and keep your deal on track.
For sellers
- Test pre-listing if possible. A long-term test is ideal, but a professional short-term test is better than none.
- If levels are elevated, consider mitigating before listing and share the post-mitigation result. You can also disclose the result and offer a credit, or agree in the contract to mitigate.
- Benefits include fewer surprises in escrow, stronger buyer confidence, and smoother closing timelines.
For buyers
- Include a radon contingency in your offer so you can test during inspections.
- Use a qualified professional or reputable kit under closed-house conditions.
- If results are 4.0 pCi/L or higher, negotiate a seller-paid mitigation, a credit, or an escrow holdback. Require post-mitigation testing and documentation.
For new residents
- If your home has not been tested, run a long-term test in your first year.
- If results are elevated, hire a certified mitigator and complete post-mitigation testing to verify the fix.
Documentation and warranties
Keep clear records. Ask for system diagrams, installation receipts, fan and workmanship warranties, and post-mitigation test results. Many mitigators set a performance guarantee in writing. Store these documents for future buyers.
Simple checklist for Manhattan homeowners
- Test every home in Gallatin County.
- Choose test type based on your timing. Use long-term for best accuracy. Use short-term for transactions.
- Follow placement and closed-house instructions exactly.
- If results are 4.0 pCi/L or higher, plan to mitigate. Consider mitigation above 2.0 pCi/L in some cases.
- Hire a certified professional and get a written plan, cost, and warranty.
- Verify success with a post-mitigation test and keep all documentation.
Ready to navigate radon with confidence as you buy or sell in Manhattan, MT? Our team can help you decide when to test, how to negotiate, and what to expect from mitigation so you can move forward with peace of mind.
Connect with Unknown Company to request a free home valuation and talk through your next steps.
FAQs
Is radon common in Manhattan, MT?
- Gallatin County is in a region with known radon potential, so every home should be tested regardless of age or neighborhood.
What is an acceptable radon level in a home?
- The EPA recommends action at 4.0 pCi/L or higher. Lower is better, and many aim for less than 2.0 pCi/L when feasible.
How long does a typical mitigation take?
- Many systems are installed in about one day, with more complex homes sometimes taking longer.
Will mitigation raise my energy bills?
- ASD systems use a small fan, so electricity use is modest. Proper sealing and design help avoid negative impacts on HVAC performance.
Does mitigation solve radon permanently?
- Mitigation provides long-term reduction, but fans and components can wear out. Plan periodic checks and repeat testing to ensure continued performance.
