City, Ogle County, Illinois
Radon Testing in Oregon, IL
Updated
IEMA has 277 radon test results on record for Oregon. 54.5% came back at or above the EPA's action level of 4.0 pCi/L. That is close to the Ogle County rate of 49.7%. A standard test runs $150 to $300. The only way to know about one specific house is to test it.
About 3,851 people live in Oregon, a Ogle County city with roughly 1,803 housing units and a median year built of 1955. It sits near Byron, Mount Morris and Rochelle. It's the Ogle County seat, on the Rock River.
What IEMA's radon test records show
Look past the median to the tail: 4.3% of Oregon tests were 20 pCi/L or more, five times the action level. The top reading on record is 110 pCi/L. The average result in Oregon is 6.83 pCi/L, against 5.98 for Ogle County overall. IEMA's own dataset covers tests licensed measurement professionals submitted from 2003 through July 2019, keeping only the highest reading on record per address. That means it is not a random sample and not year-by-year, but it is the closest thing to primary local radon data that Illinois publishes.
| Tests | Avg pCi/L | 4+ pCi/L | 10+ | 20+ | |
|---|---|---|---|---|---|
| Oregon | 277 | 6.83 | 54.5% | 20.9% | 4.3% |
| Ogle County | 1,751 | 5.98 | 49.7% | 15.7% | 3.9% |
Source: IEMA radon test records, Illinois Emergency Management Agency.
The ground under Oregon
Ogle County straddles the Rock River south of Winnebago and Boone Counties, on dolomite and limestone bedrock with Ordovician rock visible in places along the riverbanks. The EPA rates the whole county Zone 1, its highest-potential radon classification, same as the counties to its north.
Housing in Oregon
Census Bureau, American Community Survey 2020 to 2024 5-year estimates.
| Homes (housing units) | 1,803 | 22,682 in Ogle County |
| Median year built | 1955 | 1972 countywide |
| Built before 1980 | 89.1% | 71.8% countywide |
| Attached (rowhome, townhouse) | 2.1% | 2.2% countywide |
| Mobile homes | 2.1% | 2.5% countywide |
| Renter-occupied | 41.3% | 24.6% countywide |
37.2% of homes in Oregon were built before 1940, against 20.1% county-wide. Houses that old usually sit on stone or early block foundations with plenty of joints for soil gas to move through. That does not mean they cannot be tested and fixed, just that a mitigation contractor may need more than one suction point. With 41.3% of Oregon's housing renter-occupied, landlord testing questions come up often. There is no Illinois requirement to test a rental, but plenty of owners do it between tenants when the unit sits empty anyway.
What we do in Oregon
Radon testing, Buying or selling a home, and New construction.
Common questions
Is radon a problem in Oregon?
Yes. Out of 277 IEMA-recorded tests taken in Oregon, 54.5% came in at 4.0 pCi/L or higher, the EPA's action level. That fits Ogle County's overall Zone 1 rating, the agency's highest-potential class.
What is the highest radon reading on record near Oregon?
110 pCi/L, out of 277 IEMA-recorded tests. That is an outlier, not typical, but it shows why testing rather than guessing matters: neighboring houses can differ by a wide margin.
I rent in Oregon. Can I get my unit tested?
Nothing in Illinois law stops a tenant from asking for a radon test, and plenty of landlords in Oregon test between leases anyway, since an empty unit is the easiest time to do it.
Nearby
Byron (50.3% of tests at 4+ pCi/L), Mount Morris (71.9% of tests at 4+ pCi/L), Rochelle (41.4% of tests at 4+ pCi/L).
Need radon testing booked in Oregon?
Tell us why you're testing and any deadline you're working against. You get a fixed price and a straight answer back.