Ohio · county radon data
Radon in Cuyahoga County, Ohio
21.7% of the 8,861 home radon tests on record here reached the EPA action level — toward the lower end of the state's tested counties, ranked #87 of 88 tested Ohio counties.
What the numbers say
Cuyahoga County sits 32.1 points below the Ohio median (53.8% of tests over the limit across the state's counties). The median reading among its 8,861 reported tests was 2 pCi/L — and the single highest test on record reached 56.4 pCi/L, more than 14× the action level. EPA maps place the county in Radon Zone 2 — moderate predicted potential (2–4 pCi/L average screening levels), which still produces plenty of homes over the limit.
Why: the ground under Cuyahoga County
Covered by glacial till that ground up and redistributed Ohio's shale and carbonate bedrock. The till concentrates fine radioactive minerals while outwash sands provide fast pathways for soil gas — the reason most of Ohio is EPA Zone 1 or 2.
Geology sources: USGS WRI 98-4169 · EPA OH zone documentation.
The housing stock factor
The median Cuyahoga County home dates to 1957 — decades before radon-resistant new construction entered building codes. With 1,245,873 residents largely housed in that older stock, testing is the only way any individual household knows where it stands.
ZIP codes in Cuyahoga County
Ohio doesn't publish ZIP-level test results, so these ZIPs share the county figures above — the roster is here so you can confirm your address is covered by this data.
| ZIP | Place |
|---|---|
| 44017 | Berea |
| 44022 | Chagrin Falls |
| 44040 | Gates Mills |
| 44070 | North Olmsted |
| 44101 | Cleveland |
| 44102 | Cleveland |
| 44103 | Cleveland |
| 44104 | Cleveland |
| 44105 | Cleveland |
| 44106 | Cleveland |
| 44107 | Lakewood |
| 44108 | Cleveland |
| 44109 | Cleveland |
| 44110 | Cleveland |
| 44111 | Cleveland |
| 44112 | Cleveland |
| 44113 | Cleveland |
| 44114 | Cleveland |
| 44115 | Cleveland |
| 44116 | Rocky River |
| 44117 | Euclid |
| 44118 | Cleveland |
| 44119 | Cleveland |
| 44120 | Cleveland |
| 44121 | Cleveland |
| 44122 | Beachwood |
| 44123 | Euclid |
| 44124 | Cleveland |
| 44125 | Cleveland |
| 44126 | Cleveland |
| 44127 | Cleveland |
| 44128 | Cleveland |
| 44129 | Cleveland |
| 44130 | Cleveland |
| 44131 | Independence |
| 44132 | Euclid |
| 44133 | North Royalton |
| 44134 | Cleveland |
| 44135 | Cleveland |
| 44136 | Strongsville |
| 44137 | Maple Heights |
| 44138 | Olmsted Falls |
| 44139 | Solon |
| 44140 | Bay Village |
| 44141 | Brecksville |
| 44142 | Brookpark |
| 44143 | Cleveland |
| 44144 | Cleveland |
| 44145 | Westlake |
| 44146 | Bedford |
| 44147 | Broadview Heights |
| 44149 | Strongsville |
Cuyahoga County in the Ohio picture
| Cuyahoga County | 21.7% over the limit | 8,861 tests |
| Ohio's highest: Pickaway County | 81.4% | 154 tests |
| Ohio county median | 53.8% | 88 counties ranked |
| Share of all Ohio tests from this county | 10.5% | |
Ranked nearby in Ohio
- Geauga County — #84, 23.4% of 1,382 tests over the limit
- Mahoning County — #85, 23.4% of 556 tests over the limit
- Paulding County — #86, 23.1% of 12 tests over the limit
- Meigs County — #88, 20% of 16 tests over the limit
(Ranking neighbors — counties adjacent in the Ohio test ranking, not necessarily on the map.)
High test? Fixes and real pricing: the Ohio mitigation cost guide. Every statistic here traces to the methodology (CDC EPHT (labs), 2008–2017; zones: EPA; year built & population: ACS 5-year).
Cuyahoga County radon FAQ
- Is radon high in Cuyahoga County?
- 21.7% of 8,861 home tests reported to the CDC came back at or above the EPA action level of 4 pCi/L — 32.1 points below the Ohio county median of 53.8%, ranking #87 of 88 tested counties. EPA classifies the county as Zone 2.
- Does an older home in Cuyahoga County mean more radon risk?
- The county's median home was built in 1957 — before radon-resistant construction practices entered building codes in the 1990s, so most of the housing stock has no built-in radon protection. Construction age changes the odds, not the answer: only a test tells you about your house.
- Where do these Cuyahoga County numbers come from?
- 8,861 aggregated home tests in the CDC's Environmental Public Health Tracking dataset (CDC EPHT 2008-2017). Median reading: 2 pCi/L; the highest recorded test hit 56.4 pCi/L. How we handle the data, including its limits, is documented on our methodology page.
- What's the highest radon reading recorded in Cuyahoga County?
- 56.4 pCi/L — 14× the EPA action level — against a county median of 2 pCi/L across 8,861 tests. That spread is the point: neighboring homes routinely test wildly differently.