Radon Testing & Mitigation in Westerville
Westerville straddles Franklin and Delaware counties — and Delaware County consistently produces some of Ohio’s highest residential radon readings. If your home sits in the northern or eastern portions of Westerville, your radon risk is especially elevated. Carl Woolwine has tested dozens of Westerville homes and knows this community’s radon patterns well.
Westerville’s Radon Risk Is Higher Than Most Homeowners Realize
Westerville straddles Franklin and Delaware counties. The southern half sees ~40% of homes above 4.0 pCi/L; the northern and eastern sections — in Delaware County — push that figure to nearly 50%. Most homeowners here don’t know which side of that line they’re on.
Delaware County sits above limestone and dolomite topped with glacial till — ideal conditions for uranium decay and radon migration. Homes from the 1960s–1980s in Westerville’s core are especially susceptible: poured concrete with hairline cracks, block foundations with mortar gaps, and open sump pits are all common radon entry points.
Why Westerville’s Homes Are Particularly at Risk
Westerville’s residential stock is a mixed bag from a radon standpoint. The original city center features post-war and 1960s ranches and split-levels — many with poured concrete basements that have developed hairline cracks over decades. The suburban expansion that pushed north into Delaware County through the 1980s and 1990s brought ranch homes and two-stories with full basements, many on lots where the soil is rich with radon-producing glacial material. Even newer construction in the Lewis Center/Polaris corridor should not be assumed safe — Delaware County’s geology produces enough radon pressure to overcome passive RRNC features in many cases, and Carl has tested newer homes here that came in above 6 pCi/L.
Questions from Westerville Homeowners
Does radon risk differ between the Franklin County and Delaware County parts of Westerville?
Yes, meaningfully. Homes in the Delaware County portion of Westerville — north of roughly Schrock Road, and extending toward Powell and Lewis Center — sit in one of Ohio’s highest-risk counties, where nearly half of homes test above 4.0 pCi/L. The Franklin County portion still carries significant risk (~40% of homes), but the Delaware County side is notably more active. If you’re unsure which county your home is in, your county auditor’s website will confirm it — and Carl can give you local context over the phone.
My Westerville home was built in the 1970s. Is it more likely to have high radon?
Older construction doesn’t cause radon — the geology does — but 1970s homes often have foundation characteristics that make radon entry easier. Poured concrete develops hairline cracks over 50+ years. Block foundations have mortar joints that can degrade. Older utility penetrations are frequently unsealed. Carl has consistently found higher readings in Westerville’s 1960s–1980s stock compared to newer homes, even on the same street. Testing is the only way to know for certain.
I’m buying a home in Westerville. Should radon testing be part of my inspection contingency?
Absolutely. Radon testing has become a routine part of real estate transactions across the Columbus metro, and Westerville’s elevated Delaware County risk makes it especially important in the northern and eastern portions of the city. Carl offers 48-hour expedited testing that fits within standard inspection contingency windows. If levels require mitigation, he can typically complete an installation within 1–2 business days of your decision to proceed.
How does Carl’s mitigation process work for a typical Westerville basement home?
Most Westerville homes with basements are good candidates for Active Sub-Slab Depressurization (ASD). Carl drills a small hole through the basement slab, installs a PVC pipe, and connects a continuously running fan that draws radon from beneath the foundation before it enters your living space, routing it safely above the roofline. The system is quiet, low-maintenance, and backed by a written guarantee: levels below 4.0 pCi/L, or Carl returns and fixes it at no charge.
What are typical radon levels Carl sees in Westerville?
Carl has seen a wide range — from homes that test below 2.0 pCi/L (well within safe range) to homes with basement readings exceeding 12 pCi/L. The average reading in Delaware County hovers around 5.8 pCi/L, but averages mask the full story. A home’s specific foundation type, sub-slab material, and ventilation characteristics matter far more than county averages. The only accurate number for your home is the one from your test.
Sources: U.S. EPA — Radon · Ohio Dept. of Health Radon Program
Test your Westerville home with Carl.
Licensed Ohio professional, 48-hour results, written guarantee. Delaware County · ODH #RC362 & #RS579.
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