Lawrence, Eudora, Baldwin City and Lecompton are all in Douglas County. This page pulls together the public radon data that exists for the county, explains where each number comes from, and covers what those numbers can and cannot tell you about your own home. Data checked October 18, 2026.
The EPA's radon zone for Douglas County, its highest potential category. Zone 1 counties have a predicted average indoor screening level greater than 4 pCi/L (EPA Map of Radon Zones, 1993).
Average of 7,177 radon measurements from Douglas County in KDHE and Kansas State University data collected through June 2018.
Share of those measurements at or above 4 pCi/L: 1,951 of 7,177.
The EPA action level. The EPA recommends fixing a home at or above 4 pCi/L and says to consider fixing it between 2 and 4 pCi/L.
The Kansas Radon Program, run by Kansas State University Engineering Extension with the Kansas Department of Health and Environment (KDHE), publishes average radon maps for every Kansas county. The Douglas County map in the program's 2019 county map set lists these figures, based on data collected by KDHE through June 2018:
For comparison, the statewide map from the same program, using data through June 2018, lists an average of 4.6 pCi/L across 161,690 Kansas measurements, with 62,555 (about 39%) at 4 pCi/L or greater.
The same Douglas County map shades each ZIP code area by its average result:
No ZIP code in the county was shaded in the lowest range (below 2.0 pCi/L). KDHE and K-State note that the map cannot be used to predict the radon level at any specific location, so a ZIP code in the lower shading still needs a test.
The CDC's National Environmental Public Health Tracking Network publishes yearly radon test results from laboratories for each county. These are results from pre-mitigation tests, meaning tests taken before any radon system was installed.
| Year | Tests | Buildings tested | Median (pCi/L) | Average (pCi/L) |
|---|---|---|---|---|
| 2022 | 868 | 535 | 1.8 | 3.6 |
| 2021 | 2,901 | 637 | 2.0 | 3.8 |
| 2020 | 947 | 703 | 2.1 | 3.5 |
| 2019 | 1,136 | 766 | 1.7 | 3.2 |
| 2018 | 1,173 | 728 | 2.0 | 3.8 |
| 2017 | 1,498 | 715 | 1.4 | 3.0 |
| 2016 | 850 | 644 | 1.9 | 3.4 |
From 2016 through 2020, between 23.4% and 29.2% of these tests each year were at or above 4 pCi/L (28.5% in 2020). 2022 was the most recent year published for Douglas County when we checked.
The only way to know your level is to test. Start with how radon testing works in Lawrence. If your result is 4 pCi/L or higher, read about radon mitigation, and see our radon testing and mitigation cost guide. If you are buying or selling, see radon in a home sale. We also have local guides for Eudora and Baldwin City.
KDHE and Kansas State University data collected through June 2018 lists an average of 3.7 pCi/L across 7,177 Douglas County measurements. In the CDC Tracking Network's 2022 data, the average pre-mitigation test in the county was 3.6 pCi/L and the median was 1.8 pCi/L.
In the KDHE and K-State data through June 2018, 1,951 of 7,177 measurements (about 27%) were at or above the EPA action level of 4 pCi/L. In CDC Tracking Network data for 2016 through 2020, the share of pre-mitigation tests at or above 4 pCi/L ranged from 23.4% to 29.2% per year. These figures count tests, not homes.
Yes. The EPA places Douglas County, including Lawrence, in Radon Zone 1, the highest of its three categories. The EPA also says homes in every zone should be tested.
No. KDHE and K-State state that their maps cannot predict the radon level at any specific location. The EPA also notes that homes with elevated radon have been found in all three of its radon zones, so a test is the only way to know your level.
Sources: Kansas Radon Program county map (KDHE and K-State, data through June 2018) · Kansas Radon Program 2019 county maps, Douglas County · CDC National Environmental Public Health Tracking Network, Radon Testing · EPA Map of Radon Zones · EPA Kansas radon zone map (PDF). Data checked October 18, 2026.
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