Radon Testing & Mitigation in Newark
It’s now official — and national news. A 2025 Harvard University study identified Newark’s 43055 ZIP code as having the highest residential radon concentration in the entire United States. If you own a home in Newark, Heath, Granville, Pataskala, or anywhere in Licking County, radon testing isn’t a nice-to-have. It’s the single most important indoor air measurement you can make.
Licking County Isn’t Just High-Risk — It’s the Highest in America
Roughly 3 in 4 Licking County homes test at or above the EPA action level of 4.0 pCi/L — the highest county-level rate in the nation, with average readings running at roughly double the EPA limit. The 2025 Harvard study put Newark’s 43055 ZIP code at the very top of every ZIP code in the country. Most homeowners here still haven’t tested.
The driver is geology: Licking County sits where uranium-bearing black shale meets thick, permeable glacial deposits — a combination that continuously generates radon and channels it upward into foundations. It doesn’t matter whether your home is an 1890s Victorian near downtown Newark or new construction toward Pataskala; the source is under the soil, not in the house.
Why Newark’s Homes Are Particularly at Risk
Newark’s housing stock spans more than a century — late-1800s and early-1900s homes around the historic downtown core, post-war ranches and split-levels through the mid-century neighborhoods, and newer construction pushing west toward Pataskala and south toward Heath. Every era of it is exposed to the same geology. The older stock adds entry pathways: stone and block foundations, unsealed utility penetrations, open sump crocks, and decades of settling cracks. Granville’s and Heath’s housing follows the same pattern. Carl tests and mitigates all of it — and in Licking County, post-mitigation readings routinely show some of the most dramatic before/after drops he sees anywhere in Ohio.
Questions from Newark Homeowners
Is it true that Newark has the highest radon in the country?
Yes. A 2025 Harvard University study analyzing residential radon data nationwide identified Newark’s 43055 ZIP code as having the highest residential radon concentration in the United States. Licking County as a whole sees roughly 75% of homes test at or above the EPA action level of 4.0 pCi/L — the kind of rate that makes testing essential for every home, not just older ones.
Why is Licking County’s radon so extreme?
Geology. The county sits on uranium-bearing black shale overlaid with permeable glacial deposits — the shale continuously produces radon, and the loose glacial material gives it an easy path upward into basements and crawl spaces. This combination exists in much of Ohio, but it is especially concentrated in the Newark area, which is why Licking County tops national rankings rather than just state ones.
I live in Newark and have never tested. How urgent is this?
Test now — not because radon is an emergency in any given week, but because the risk is cumulative and the odds are against you here. With ~3 in 4 homes above the limit and average readings around double the EPA action level, the statistically likely outcome is that your home needs mitigation. A 48-hour CRM test settles it for less than the cost of a tank of gas, and Carl typically schedules Licking County within 1–3 business days.
My Newark home is over 100 years old with a stone foundation. Can it even be mitigated?
Yes. Older Newark homes — stone foundations, dirt-floor cellars, block walls — require more careful system design than a modern poured basement, but Carl has mitigated all of these configurations. Approaches range from sub-slab depressurization where slabs exist to sub-membrane systems over exposed soil. Every installation carries the same written guarantee: below 4.0 pCi/L, or Carl returns and fixes it at no charge.
Does Carl serve all of Licking County or just Newark?
All of it — Newark, Heath, Granville, Pataskala, Johnstown, Hebron, Buckeye Lake, and surrounding communities. Licking County is part of Carl’s core Central Ohio service area, and given the county’s national ranking, he prioritizes scheduling here. Call (614) 686-0000 and mention your town.
Sources: U.S. EPA — Radon · Ohio Dept. of Health Radon Program
Test your Newark home with Carl.
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