Dataset · v1.0.0 · 98 rows
Radon test results by ZIP code: DuPage, Kane and Will
Licensed radon measurement results submitted to IEMA-OHS, aggregated by ZIP code for DuPage, Kane and Will counties: tests, share at or above 4.0 pCi/L, median, mean and maximum.
The data
| County | ZIP code | Valid tests (tests) | Share at or above 4.0 pCi/L (percent) | Median result (pCi/L) | Mean result (pCi/L) | Highest result (pCi/L) |
|---|---|---|---|---|---|---|
| DuPage | 60540 | 3690 | 47.9 | 3.8 | 5.4 | 74.5 |
| DuPage | 60137 | 2773 | 41.5 | 3.3 | 5.1 | 154.2 |
| DuPage | 60189 | 2384 | 48.3 | 3.8 | 5.6 | 58.7 |
| DuPage | 60126 | 2312 | 32.4 | 2.8 | 3.9 | 52.2 |
| DuPage | 60563 | 1945 | 44.5 | 3.5 | 4.9 | 94.6 |
| DuPage | 60565 | 1843 | 48.6 | 3.8 | 5.5 | 68.5 |
| DuPage | 60187 | 1679 | 44.1 | 3.5 | 5 | 51.2 |
| DuPage | 60521 | 1670 | 35.6 | 3 | 4.1 | 34.1 |
| DuPage | 60502 | 1575 | 31.4 | 2.8 | 3.6 | 33.2 |
| DuPage | 60148 | 1553 | 38.1 | 3.1 | 4.6 | 57 |
| DuPage | 60515 | 1550 | 43 | 3.5 | 5.2 | 56.1 |
| DuPage | 60532 | 1333 | 48.3 | 3.8 | 6 | 56.4 |
| DuPage | 60504 | 1306 | 33.2 | 2.6 | 3.8 | 46.3 |
| DuPage | 60516 | 1255 | 44.2 | 3.6 | 5.1 | 48.6 |
| DuPage | 60517 | 944 | 38.7 | 2.9 | 4.4 | 36.5 |
| DuPage | 60103 | 914 | 34.7 | 2.8 | 4.3 | 65 |
| DuPage | 60185 | 901 | 50.1 | 4 | 5.5 | 81.2 |
| DuPage | 60108 | 894 | 32.4 | 2.3 | 4.1 | 37.4 |
| DuPage | 60561 | 888 | 38.6 | 3.2 | 4.5 | 57 |
| DuPage | 60527 | 874 | 37.6 | 3.2 | 4.6 | 42 |
| DuPage | 60188 | 862 | 28.5 | 2.5 | 3.6 | 99.1 |
| DuPage | 60564 | 854 | 32.8 | 3 | 3.9 | 34.6 |
| DuPage | 60514 | 749 | 33 | 2.9 | 4.1 | 40.7 |
| DuPage | 60190 | 734 | 46 | 3.5 | 5 | 48.7 |
| DuPage | 60181 | 728 | 30.2 | 2.6 | 3.6 | 36.5 |
| DuPage | 60559 | 722 | 36.1 | 3 | 4.3 | 42.4 |
| DuPage | 60523 | 613 | 36.1 | 3 | 4.5 | 66 |
| DuPage | 60172 | 453 | 39.3 | 3.1 | 5 | 63.5 |
| DuPage | 60101 | 440 | 34.1 | 2.9 | 4.5 | 66.2 |
| DuPage | 60555 | 419 | 41.3 | 3 | 5.3 | 34.8 |
| DuPage | 60139 | 260 | 20.4 | 1.9 | 3.1 | 23.2 |
| DuPage | 60143 | 230 | 47 | 3.6 | 5.1 | 32.4 |
| DuPage | 60133 | 173 | 22 | 1.9 | 2.8 | 17.3 |
| DuPage | 60191 | 167 | 31.1 | 2.8 | 3.6 | 16.2 |
| DuPage | 60439 | 147 | 39.5 | 2.9 | 4.6 | 47.7 |
| DuPage | 60106 | 143 | 27.3 | 2.5 | 3.5 | 27 |
| DuPage | 60184 | 91 | 61.5 | 5 | 5.9 | 17.2 |
| DuPage | 60157 | 70 | 48.6 | 3.8 | 5.8 | 33.6 |
| DuPage | 60440 | 44 | 18.2 | 1.8 | 2.9 | 17.9 |
| DuPage | 60174 | 36 | 8.3 | 1.7 | 1.9 | 6.2 |
Showing the first 40 of 98 rows. The complete dataset is in the downloads below — the cap is on rendering, not on the data.
Download and API
- radon-test-results-by-zip-dupage-kane-will.csv — 98 rows, comma separated.
- radon-test-results-by-zip-dupage-kane-will.json — rows plus the field schema, methodology, and version. Stable URL, same origin, no key required.
- index.json — the catalogue of every dataset, for programmatic discovery.
Licence. CC BY 4.0 — reuse with attribution to Radon Connect and a link to the dataset page.
Field schema
| Field | Type | Description |
|---|---|---|
county | string | County as recorded on the measurement (a ZIP that straddles a county line appears once per county). |
zip | string | Five-digit ZIP code of the tested address. |
tests | number (tests) | Licensed measurements IEMA-OHS recorded as valid, in homes without a mitigation system at the time of the test. |
shareAtOrAbove4 | number (percent) | Percentage of those tests at or above the EPA action level of 4.0 pCi/L. |
medianPciL | number (pCi/L) | The 50th percentile of results in the ZIP — the better summary of a typical home. |
meanPciL | number (pCi/L) | Arithmetic mean; pulled upward by a small number of very high results. |
maxPciL | number (pCi/L) | The single highest valid result recorded in the ZIP. |
Methodology
The question this answers
What have licensed radon tests found, ZIP by ZIP, in DuPage, Kane and Will counties?
How a row comes to exist
- On 2 September 2026 the public ArcGIS feature service behind the IEMA-OHS Public Radon Dashboard (Radon_Full/FeatureServer/0, "RadonLicensedMeasurements", 544,664 rows statewide) was queried for grouped statistics per ZIP: the count of results, their mean, their maximum, their 50th percentile, and the count of results at or above 4.0 pCi/L.
- Share at or above 4.0 pCi/L is the second count divided by the first, in percent, rounded to one decimal place. Results are rounded to one decimal place.
- No individual measurement, address, licensee name or device serial number was requested or stored; the service was asked only for aggregates.
Inclusion and exclusion
- Measurements whose county is Du Page, Kane or Will, whose InvalidReason is N (recorded as valid) and whose HasMigationSystem is N (no mitigation system present at the time of the test).
- ZIP codes with at least 20 such measurements. Smaller ZIPs are excluded because a handful of tests does not describe a ZIP.
- A ZIP that straddles a county line appears once per county, carrying only that county’s measurements.
What this dataset cannot tell you
- These are results from tests performed by licensed professionals and reported to the state. Homeowner self-test kits are not in the service, so the sample leans toward real-estate transactions and follow-up testing.
- The service exposes no machine-readable test date, so the period covered is not computed here. IEMA-OHS describes the dashboard as the licensed measurements submitted to it, and its description governs.
- A ZIP statistic predicts nothing about any single house. Neighbouring homes routinely test on opposite sides of 4.0 pCi/L; only a test of the house in question answers for that house.
- The mean is pulled upward by a small number of very high results; the median is the better summary of a typical home in the ZIP.
- IEMA-OHS has not reviewed this table. Any aggregation error is ours; the underlying records are the agency’s.
Related
- Radon Connect Coverage Index — Every market, territory, and city page this platform publishes, as one table.
- State Radon Regulatory Index — Ten states, one table: regime, agency, disclosure mechanism, and what is actually required.
- How testing works — Devices, placement, closed-building conditions, and what invalidates a result.
- Research Center — every dataset, with its provenance and status.
- Research methodology — how this platform builds and checks content.
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