Pennsylvania Radon - Test Results & Mitigation Systems

Two Pennsylvania radon registers from the Department of Environmental Protection, published as public open data on data.pa.gov - every recorded radon measurement (homes, schools and non-residential buildings), and every mitigation system installed to fix one.

Low cost

From $0.00005 per record, down to $0.00003 at Gold. Pay only for the records you actually receive - the whole register stays queryable, you are never billed for the scan behind it.

What you get

Pick a register with corpus:

corpus=testing (default) - radon test results

3.33 million measurements, from 1986 through July 2026. 99.9998% carry a real numeric reading in pCi/L.

• Where - county, municipality, ZIP
• What building - purpose (Residential / School / Non-Residential), building type and sub-type
• The test - the floor tested, the test method, and the two test dates
• The result - the reading in pCi/L

corpus=mitigation - mitigation systems

~527k systems, through October 2026.

• Where - county, municipality, ZIP and coordinates (the coordinates are county-level centroids, not site-level locations)
• What building - purpose, building type, floor tested
• The fix - the remediation system installed, whether the test was pre- or post-mitigation, and the system cost
• The reading - the radon level at that system's test

The two registers cannot be joined

Their identifiers live in different namespaces - a testing row carries a radon_data_identifier in roughly the 5-11 digit range plus a small integer result id; a mitigation row carries a much shorter dataidentifier and a formatted result id (31646-0584-1-2). No key is shared between the two registers. They are offered side by side as two ends of one story - a measurement and the fix installed after it - never as linkable.

Filter it

• County, municipality, ZIP - county="Allegheny", municipality="Pittsburgh", postalCode="19148".
• Radon level - minValue=4 finds every result at or above the EPA action level of 4 pCi/L (1,123,051 of 3.33M test results).
• Floor, building purpose, test method.
• Remediation - remediationSystem="Sub-Slab Ventilation", minCost=1500 (mitigation register).
• Date range on the test end date, and last-N-days.

Example inputs

Tests at or above the EPA action level - the headline query.

{ "corpus": "testing", "minValue": 4, "maxResults": 50 }

One county's radon picture - filter and aggregate in one register.

{ "corpus": "testing", "county": "Montgomery", "mode": "aggregate", "groupBy": "buildingType" }

What mitigation costs - the systems installed, and their cost.

{ "corpus": "mitigation", "minCost": 1500, "maxResults": 50 }

Or roll it up

Set mode=aggregate for a rolled-up count by county, building purpose, building type, floor tested, test method, remediation system or device type. Dimensions differ per register; remediationSystem/deviceType are mitigation-only and testMethod is testing-only (the mitigation register stores a bare equipment code with no legend, so that field is left blank there). Every group comes back - not cut off by maxResults.

Then follow the money and the risk

• Every home radon reading in a county, and the share above 4 pCi/L.
• Which remediation systems are installed where, and at what cost.
• Radon by building type, floor and test method - basement vs. first floor.
• The mitigation record for a ZIP code, with county-level coordinates.

Example output

One mitigation system - corpus=mitigation, county=Allegheny:

{
 "platform": "pa-radon",
 "source": "pa-radon-mitigation",
 "mode": "rows",
 "groupKey": "",
 "groupCount": "",
 "groupBy": "",
 "dataIdentifier": "517274",
 "testResultIdentifier": "372377-3322-1-2",
 "county": "Allegheny",
 "municipality": "IMPERIAL",
 "postalCode": "15126",
 "buildingPurpose": "Residential",
 "buildingType": "2-STORY",
 "buildingSubType": "",
 "floorTested": "BASEMENT",
 "testMethod": "",
 "measureValue": "0.5",
 "testStartDate": "",
 "testEndDate": "2026-06-20T00:00:00.000",
 "dataSource": "Pennsylvania Department of Environmental Protection",
 "deviceType": "",
 "remediationSystem": "ACTIVATE A PASSIVE SYSTEM",
 "mitigationTestType": "POST",
 "mitigationYear": "2026",
 "systemCost": "775",
 "latitude": "40.46735543",
 "longitude": "-79.98619843",
 "corpus": "mitigation",
 "sourceUpdatedAt": "2026-10-13"
}

mode=aggregate, groupBy=county (testing) - one count row per county:

Montgomery                      391,126
Allegheny                       356,402
Bucks                           292,080
Chester                         261,523
Delaware                        193,590
Philadelphia                    193,339

Notes on the data, from the source

• Readings are in pCi/L (picocuries per litre). The EPA action level is 4 pCi/L; the value is returned exactly as measured.
• Two registers, not one table. See above - they cannot be joined.
• Mitigation coordinates are county-level centroids. The source carries only 67 distinct points for ~527k systems, so use county for geography; the coordinates do not identify a site.
• deviceType is sparse on the mitigation register - it is recorded on about a quarter of rows, so its roll-up returns a large (blank) group.
• Two columns in the testing register are dead and are not exposed. The mitigation-system indicator holds a single value across all 3.33M rows, and the census tract is filled on 6.6% of rows. Exposing either would promise a filter that cannot narrow anything.
• "Not Collected" and "Unknown" are values the source publishes, not missing data.
• The registers are refreshed annually (the State's own update frequency), not daily; sourceUpdatedAt carries the dataset's own refresh date.