Michigan · county radon data
Radon in Oakland County, Michigan
28.8% of the 12,288 home radon tests on record here reached the EPA action level — mid-pack for the state, ranked #22 of 83 tested Michigan counties.
What the numbers say
Oakland County sits 12.2 points above the Michigan median (16.6% of tests over the limit across the state's counties). The median reading among its 12,288 reported tests was 2.3 pCi/L — and the single highest test on record reached 2297 pCi/L, more than 574× 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 Oakland County
Covered in thick glacial drift over the Michigan Basin's sedimentary rocks. Radon potential is moderate for most of the state, but tills incorporating shale or carbonate fragments can push individual homes well over the action level — testing is the only way to know. (Regional attribution here is well supported; unit-level detail is coarser — see methodology.)
Geology sources: USGS WRI 98-4169 · EPA MI zone documentation.
The housing stock factor
The median Oakland County home dates to 1975 — decades before radon-resistant new construction entered building codes. With 1,279,825 residents largely housed in that older stock, testing is the only way any individual household knows where it stands.
ZIP codes in Oakland County
Michigan 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 |
|---|---|
| 48009 | Birmingham |
| 48017 | Clawson |
| 48025 | Franklin |
| 48030 | Hazel Park |
| 48033 | Southfield |
| 48034 | Southfield |
| 48067 | Royal Oak |
| 48069 | Pleasant Ridge |
| 48070 | Huntington Woods |
| 48071 | Madison Heights |
| 48072 | Berkley |
| 48073 | Royal Oak |
| 48075 | Southfield |
| 48076 | Southfield |
| 48083 | Troy |
| 48084 | Troy |
| 48085 | Troy |
| 48098 | Troy |
| 48165 | New Hudson |
| 48167 | Northville |
| 48178 | South Lyon |
| 48220 | Ferndale |
| 48237 | Oak Park |
| 48301 | Bloomfield Hills |
| 48302 | Bloomfield Hills |
| 48304 | Bloomfield Hills |
| 48306 | Rochester |
| 48307 | Rochester |
| 48309 | Rochester |
| 48320 | Keego Harbor |
| 48322 | West Bloomfield |
| 48323 | West Bloomfield |
| 48324 | West Bloomfield |
| 48326 | Auburn Hills |
| 48327 | Waterford |
| 48328 | Waterford |
| 48329 | Waterford |
| 48331 | Farmington |
| 48334 | Farmington |
| 48335 | Farmington |
| 48336 | Farmington |
| 48340 | Pontiac |
| 48341 | Pontiac |
| 48342 | Pontiac |
| 48346 | Clarkston |
| 48348 | Clarkston |
| 48350 | Davisburg |
| 48356 | Highland |
| 48357 | Highland |
| 48359 | Lake Orion |
| 48360 | Lake Orion |
| 48362 | Lake Orion |
| 48363 | Oakland |
| 48367 | Leonard |
| 48370 | Oxford |
| 48371 | Oxford |
| 48374 | Novi |
| 48375 | Novi |
| 48377 | Novi |
| 48380 | Milford |
+8 more — look yours up in the ZIP tool.
Oakland County in the Michigan picture
| Oakland County | 28.8% over the limit | 12,288 tests |
| Michigan's highest: Lenawee County | 56.7% | 1,349 tests |
| Michigan county median | 16.6% | 83 counties ranked |
| Share of all Michigan tests from this county | 14.9% | |
Ranked nearby in Michigan
- Barry County — #19, 30.7% of 1,078 tests over the limit
- Cass County — #20, 30.4% of 449 tests over the limit
- Monroe County — #21, 30.4% of 1,065 tests over the limit
- Huron County — #23, 26.5% of 196 tests over the limit
- Ingham County — #24, 24.9% of 2,399 tests over the limit
- Berrien County — #25, 24.2% of 1,030 tests over the limit
(Ranking neighbors — counties adjacent in the Michigan test ranking, not necessarily on the map.)
High test? Fixes and real pricing: the Michigan mitigation cost guide. Every statistic here traces to the methodology (CDC EPHT (labs), 2008–2017; zones: EPA; year built & population: ACS 5-year).
Oakland County radon FAQ
- Is radon high in Oakland County?
- 28.8% of 12,288 home tests reported to the CDC came back at or above the EPA action level of 4 pCi/L — 12.2 points above the Michigan county median of 16.6%, ranking #22 of 83 tested counties. EPA classifies the county as Zone 2.
- Does an older home in Oakland County mean more radon risk?
- The county's median home was built in 1975 — 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 Oakland County numbers come from?
- 12,288 aggregated home tests in the CDC's Environmental Public Health Tracking dataset (CDC EPHT 2008-2017). Median reading: 2.3 pCi/L; the highest recorded test hit 2297 pCi/L. How we handle the data, including its limits, is documented on our methodology page.
- What's the highest radon reading recorded in Oakland County?
- 2297 pCi/L — 574× the EPA action level — against a county median of 2.3 pCi/L across 12,288 tests. That spread is the point: neighboring homes routinely test wildly differently.