Radon Mitigation in Lima, OH
Lima is the largest city in Allen County and a regional hub for Northwest Ohio, EPA Radon Zone 1. Lima's geology combines Silurian and Devonian limestone bedrock with glacial till from the Wisconsinan and Illinoian glaciations. Some of Allen County's elevated radon readings come from karst features in the limestone bedrock that allow soil gas to channel into basements.
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Why Do Lima Homes Have Elevated Radon?
Geology: Lima sits on Silurian and Devonian limestone bedrock overlain by glacial till. Some areas show karst (cave-forming) limestone features that channel soil gas. The clay-rich till provides a partial seal that concentrates radon under basements.
Permits: Lima Department of Building Inspections building permits may apply to slab penetration or exterior venting work. Ohio Department of Health (ODH) Radon Licensing per Ohio Admin. Code Chapter 3701-69 is required for any radon mitigation contractor performing work in Lima.
Neighborhoods we serve in Lima: Downtown, Eastside, Westside, Spencerville, Elida, Bath Township, Shawnee Township, American Township.
All Lima radon work is performed by NRPP-certified, ODH-certified partner contractors routed through Ohio Radon Experts.
How Does Lima Compare on Ohio Radon Levels?
Allen County averages 4.4 pCi/L indoor radon — well above the EPA action level of 4 pCi/L. Here's how Lima's radon profile compares to other Ohio cities we serve.
| Metric | Lima, OH | Ohio State Average | US National Average |
|---|---|---|---|
| Average indoor radon | 4.4 pCi/L | 4.7 pCi/L | 1.3 pCi/L |
| EPA Radon Zone | Zone 1 | Zone 1 (majority) | Varies (Zones 1–3) |
| % homes elevated (>4 pCi/L) | 35% | ~33% (1 in 3) | ~6% |
| Multiple of EPA action level | 1.1x | 2.1x | 0.3x |
| EPA action level | 4.0 pCi/L | 4.0 pCi/L | 4.0 pCi/L |
Check Your Lima Radon Test Result Against the EPA Action Level
Enter your radon test result (in pCi/L) to see whether your Lima, OH home meets the EPA action level of 4.0 pCi/L — and exactly what to do next based on official EPA guidance. Lima averages 4.4 pCi/L, with 35% of homes testing elevated.
Enter the picocuries-per-liter value from your charcoal canister or continuous radon monitor (CRM) report.
How the calculator maps test results to EPA guidance
| Radon level (pCi/L) | Risk tier | EPA-aligned recommendation |
|---|---|---|
| 0.0 – 1.9 | Below average — low | No action needed. Re-test every 2 years or after major renovation. |
| 2.0 – 3.9 | Elevated — EPA "consider mitigating" | Consider mitigation, especially with smokers, children, or lower-level bedrooms. Run a long-term (90+ day) test for confirmation. |
| 4.0 or higher | EPA Action Level — fix the home | Install an active radon mitigation system. EPA recommends fixing the home as soon as practical. |
Which Radon Services Are Available in Lima?
Radon Mitigation
Active radon mitigation system installation for Ohio homes — sub-slab depressurization is the most common method, reducing indoor …
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Radon Testing
Professional radon testing services for Ohio homes — short-term (2-7 day) and long-term (90+ day) testing options. Required for mo…
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Sub-Slab Depressurization Installation
Ohio's most common radon mitigation method — sub-slab depressurization (ASD) creates negative pressure beneath the basement slab, …
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Crawl Space Radon Mitigation
Sub-membrane depressurization for Ohio homes with crawl spaces — includes vapor barrier installation, sealing, and active depressu…
Learn more →Do Lima Real Estate Transactions Require Radon Testing?
Ohio Residential Property Disclosure Act (Ohio Rev. Code § 5302.30) requires sellers to disclose any known radon test results to buyers. In practice, most Lima real estate transactions now include a radon contingency in the purchase agreement — and given that 35% of Lima homes test elevated, buyers are increasingly insisting on pre-closing mitigation when results exceed 4 pCi/L.
Our partner contractor network handles closing-timeline mitigations within typical 7–14 day windows, including post-mitigation verification testing to satisfy lender and inspector requirements.
Are Winter Radon Levels Higher in Lima?
Yes. Lima's cold winters intensify radon entry through the stack effect — heated indoor air rising creates negative pressure in basements that pulls soil gas into the home at higher rates than warmer climates. Lima winter radon readings are typically 30–50% higher than summer readings.
EPA recommends radon testing under closed-house conditions, which align naturally with Lima winters. If your Lima home tested low in summer, retest in winter for an accurate baseline before deciding on mitigation.
Recent Lima Radon Mitigation Projects
Recent radon mitigation projects across Ohio — every image is geo-tagged to a specific Ohio city and entity-described for transparency and provenance. All work performed by NRPP-certified, ODH-certified partner contractors.
📍 Philadelphia, Ohio 
📍 Pittsburgh, Ohio 
📍 State College, Ohio 
📍 West Philadelphia, Ohio Lima, OH Radon FAQs
What are typical radon levels in Lima?
Why are Lima radon levels so high?
How do I find a certified radon mitigation contractor in Lima?
How long does it take to schedule radon mitigation in Lima?
What Other Ohio Cities Do We Serve Near Lima?
Columbus, OH
Franklin County · 4.8 pCi/L avg
Cleveland, OH
Cuyahoga County · 5.2 pCi/L avg
Cincinnati, OH
Hamilton County · 4.5 pCi/L avg
Toledo, OH
Lucas County · 4.6 pCi/L avg
Akron, OH
Summit County · 5.5 pCi/L avg
Dayton, OH
Montgomery County · 4.4 pCi/L avg
Youngstown, OH
Mahoning County · 5.8 pCi/L avg
Canton, OH
Stark County · 5 pCi/L avg
Ready to Get a Free Lima Radon Quote?
Same-day routing to a Allen County NRPP-certified partner. Written quote within 48 hours of site assessment.