About 50% of Ohio homes have radon levels above the EPA action level of 4 pCi/L, so it is very common for a radon contingency to come up in an Ohio real estate contract. Understanding how these contingencies work protects both buyers and sellers from surprises that can delay or derail a closing.
What a Radon Contingency Means in Ohio
A radon contingency is a written agreement within a purchase contract that spells out who tests, what happens if levels are high, and how mitigation or credits will be handled. It is a practical tool for managing a very common environmental issue without derailing a sale.
Why Radon Contingencies Are So Common in Ohio
Central and southern Ohio sit in areas where elevated radon is routine. The average indoor radon level in Ohio is about 7.8 to 7.9 pCi/L -- roughly double the national average -- so most buyers want a clear plan before finalizing a purchase.
Basic Elements of an Ohio Radon Contingency
- Deadline for the buyer to order and complete testing
- The type of test allowed (often a professional short-term test)
- The action level that triggers repairs or negotiation (usually 4.0 pCi/L)
- Options if results are high: mitigation, credits, or contract termination
We encourage buyers and sellers to be very specific in the contingency so there are no surprises when test results arrive. Clear language reduces conflict and keeps the focus on practical solutions.
Ohio Laws, Disclosures, and Licensing That Affect Your Contingency
Radon Disclosure Requirements
Ohio law requires sellers to disclose prior radon testing results on the Residential Property Disclosure Form if they know them. If a seller has never tested, they typically indicate "unknown," which is exactly why many buyers insist on a radon contingency. For full details, see our guide to Ohio radon disclosure requirements.
Licensed Professionals Matter
Ohio requires licensing for radon testing and mitigation professionals. Using licensed testers and installers helps both sides feel comfortable accepting results and mitigation as final, which strengthens the contingency process.
How Radon Testing Works During an Ohio Home Inspection
Most radon contingencies tie testing to the standard home inspection window, often 7 to 15 days after contract acceptance.
Professional Short-Term vs. Long-Term Tests
Short-term tests (48 to 96 hours) are the most common option in real estate because they fit contract timelines. Long-term tests capture seasonal patterns over 90 days or more but are less practical for time-sensitive contingencies.
Placement and Conditions for Valid Results
We follow EPA-style guidance by placing monitors on the lowest livable level, usually 2 to 6 feet above the floor and away from drafts or exterior doors. Windows and exterior doors remain closed except for normal entry and exit to keep conditions stable.
In a central Ohio testing wave, 54 of 68 homes tested (79.4%) were above the EPA threshold, which is why radon contingencies are becoming standard in many Ohio purchase contracts.
What Counts as "High" Radon in an Ohio Contingency?
Most Ohio contracts use 4.0 pCi/L as the trigger level. Some buyers, especially those aware of local hotspots, ask for a lower threshold such as 2.0 or 3.0 pCi/L, but that usually requires more negotiation.
Understanding Local Averages and Hotspots
Some Ohio counties report average radon levels as high as 16 pCi/L. In those areas, buyers often plan for mitigation from the start and focus contingency language on how mitigation will be completed, not whether it will be needed.
Example Threshold Language
Many contracts say something like: "If test results are at or above 4.0 pCi/L, buyer may request seller install a mitigation system or provide a closing credit." We recommend clearly stating the test method, the level, and the options both sides have.
Who Pays for Radon Mitigation Under an Ohio Contingency?
Ohio law does not mandate who pays for mitigation, so it all comes down to contract language and negotiation strength.
Typical Cost Ranges for Negotiation
Professional radon mitigation in Columbus typically costs between $800 and $2,500, with most homeowners paying around $1,200 for a complete installation.
Common Cost-Sharing Approaches
- Seller pays full cost for an installed system before closing
- Seller provides a fixed credit (for example $1,200) and buyer chooses the contractor after closing
- Buyer accepts as-is in exchange for a lower purchase price
Why Some Buyers Prefer Credits
Credits allow buyers to choose their own contractor, system design, and fan quality after closing, which some prefer for long-term reliability. Others would rather have everything done before move-in, so they push for a completed system instead. Learn more in our radon negotiation guide.
Financing Options When Contingency Repairs Strain Your Budget
Sometimes a radon contingency reveals the need for mitigation at the same time you are juggling down payments and closing costs.
0% APR and Low-Interest Plans
We help buyers and sellers explore financing that offers 0% APR for 6 to 12 months or low-interest installment plans for mitigation work. This lets a seller agree to install a system before closing without needing the full amount out of pocket.
Using Credits and Financing Together
Even if buyers arrange financing, a strong contingency can still secure meaningful seller credits at the closing table. We recommend having a rough quote from a licensed mitigator ready so credit negotiations are anchored in realistic numbers.
Using Free and DIY Testing Around Your Contingency
Free and DIY tests play a different role than professional tests in most contingencies. They are useful early screening tools, especially before you list a home or when you begin house-hunting.
Free State and Library Programs
Ohio's Indoor Radon Program and local health departments offer free charcoal test kits. In the Columbus area, public libraries also lend continuous radon monitors at no equipment cost. From 2016 through October 2025, Ohio distributed 71,434 free radon tests -- only about 1.4% of roughly 4.9 million households.
DIY Limits in Real Estate Contracts
Most formal contingencies specify a professional, third-party test to avoid disputes. However, DIY results can guide whether you decide to include a contingency in your offer or test before you even list.
What to Expect From a Mitigation System After a Contingency
Typical System Design
Most Ohio homes receive an active soil depressurization system, which uses a fan to pull radon from beneath the foundation and vent it safely outdoors. Depending on the property, this may involve sub-slab piping, crawl space encapsulation, or multiple suction points.
Cost and Scope Expectations
While typical installations range from $800 to $2,500, large homes, complex foundations, or aesthetic routing preferences can increase cost. Contracts sometimes set a maximum repair amount so sellers know the financial scope before agreeing.
Post-Mitigation Testing and Documentation
After installation, follow-up testing verifies that radon levels have dropped below the agreed threshold. We document system details, fan model, and test results so buyers have a clear record attached to their home purchase.
Seasonal Timing and Special Cases in Ohio Contingencies
Winter vs. Summer Testing
Winter tests sometimes capture higher levels due to closed-house conditions, stack effect, and reduced natural ventilation. If a test is done in summer with windows frequently open, some buyers request a follow-up winter test or an extended testing clause.
Vacant Homes and New Construction
Vacant homes can behave differently than occupied ones, so we note conditions in the report and may recommend follow-up testing after move-in. New construction often includes radon-resistant features, but testing is still essential before closing.
Homes with Planned Renovations
If buyers plan major changes to basements or HVAC systems, radon dynamics might change over time. We sometimes suggest retesting after renovations, even if a contingency test and mitigation already occurred.
How to Negotiate Fairly When Radon Shows Up
Buyer Strategies
Present the test report and at least one estimate for mitigation, then request either installation or a matching credit. You may also ask for an extension of inspection timelines if more evaluation is needed.
Seller Strategies
Get a second quote or consult a trusted local mitigator to confirm that requested credits align with real costs. Some sellers choose to install a system themselves before closing to preserve their original sale price. Consider pre-listing radon testing to get ahead of contingency requests.
Keeping the Deal Moving
Clear written proposals, realistic cost expectations, and responsive scheduling keep radon from becoming a deal-breaker. We coordinate quickly with both parties to propose solutions that respect the contract timeline.
