Radon levels in District of Columbia: Low
The model predicts a population-weighted basement average of 1.1 pCi/L (model estimate) across District of Columbia's 1 counties - about 42% below the US average of 1.8 pCi/L. Above-ground floors average 0.8 pCi/L.
Predicted (model estimate). The pCi/L figures on this page are long-term area averages from a peer-reviewed national model built on millions of real radon tests (2001-2021). They describe the typical home in this area - not your home, which can be several times higher or lower. The EPA radon zone is a separate, 1993 county-level classification. How the numbers work.
0 / 1
EPA Zone 1 counties (0%)
0 / 1
Zone 2 / Zone 3 counties
0
counties predicted ≥ 4 pCi/L
0%
of ZIP codes predicted ≥ 4 pCi/L
Test District of Columbia once anyway - radon varies house to house
The predicted basement average here is 1.1 pCi/L, below the EPA's 2 pCi/L "consider fixing" threshold. That's good news for the area - but the EPA still recommends every home be tested, because foundation cracks, soil pockets and ventilation make one house very different from its neighbor. One inexpensive kit settles it.
Monitor link goes to the Airthings store - use code RADONGRADE-10OFF at checkout for 10% off any Airthings monitor.
Affiliate links: we may earn a commission from Airthings or Amazon at no extra cost to you.
What the data says about radon in District of Columbia
0 of District of Columbia's 1 counties are EPA Zone 1 (0%), 0 are Zone 2 and 1 is Zone 3 on the EPA's county-level map. Every county is in the lowest-potential zone (predicted screening average under 2 pCi/L). The zones were drawn once, from geology and the tests available in 1993, and the EPA itself notes that homes with elevated radon exist in all three zones.
Weighted by where people live, District of Columbia's predicted basement average is 1.1 pCi/L - 42% below the US average of 1.8 - which puts the state in the low range. Of the 1 counties with predictions, 0 are predicted at or above 4 pCi/L, 0 in the 2-4 band and 1 below 2. The county range is narrow: from District of Columbia at 1.06 to District of Columbia at 1.06 pCi/L, a spread of only 0.00.
Nationally 4.2% of ZIPs are predicted at 4+ pCi/L and 48.7% at 2+; in District of Columbia it is 0% and 0% - below the national figures on both counts. No ZIP in the state is predicted above 4 on average - but averages hide individual homes, which is why the EPA still asks everyone to test.
District of Columbia counties by predicted radon
Sorted highest to lowest predicted basement average (model estimate). 1 counties.
| County | Predicted basement | Upstairs | Grade | EPA zone | ZIPs |
|---|---|---|---|---|---|
| District of Columbia | 1.1 pCi/L | 0.8 | Low | EPA Zone 3 | 22 |
Radon levels in District of Columbia cities
The one most-populous District of Columbia place among the 1,000 largest US cities (Census incorporated places and CDPs), by population. City figures are ZIP-land-weighted means of the model's ZIP predictions (model estimate).
| City | Population | Predicted basement | Upstairs | Grade | ZIPs ≥ 4 |
|---|---|---|---|---|---|
| Washington | 678,972 | 1.1 pCi/L | 0.8 | Low | 0% |
Highest-radon ZIP codes in District of Columbia
The 10 District of Columbia ZIP codes with the highest predicted basement average (model estimate), out of 22 modeled. A ZIP average is still an area figure - neighboring homes routinely test several pCi/L apart.
| ZIP | County | Predicted basement | Upstairs | Grade |
|---|---|---|---|---|
| 20012 | District of Columbia | 1.2 pCi/L | 0.9 | Low |
| 20015 | District of Columbia | 1.2 pCi/L | 1.1 | Low |
| 20018 | District of Columbia | 1.2 pCi/L | 0.9 | Low |
| 20008 | District of Columbia | 1.2 pCi/L | 0.9 | Low |
| 20007 | District of Columbia | 1.2 pCi/L | 0.7 | Low |
| 20032 | District of Columbia | 1.1 pCi/L | 0.8 | Low |
| 20017 | District of Columbia | 1.1 pCi/L | 0.8 | Low |
| 20016 | District of Columbia | 1.1 pCi/L | 0.8 | Low |
| 20001 | District of Columbia | 1.1 pCi/L | 0.8 | Low |
| 20011 | District of Columbia | 1.1 pCi/L | 0.8 | Low |
District of Columbia radon questions
- Is radon high in District of Columbia?
- District of Columbia's population-weighted predicted basement average is 1.1 pCi/L, about 42% below the US average of 1.8. 0 of its 1 modeled counties are predicted at or above the EPA action level of 4 pCi/L, 0 are in the 2-4 "consider fixing" range and 1 are below 2. 0% of District of Columbia ZIP codes are predicted at 4 or higher.
- Which District of Columbia county has the highest radon?
- District of Columbia has the highest predicted basement average in District of Columbia at 1.1 pCi/L (EPA Zone 3). The lowest is District of Columbia at 1.1 pCi/L. These are area figures; individual homes in any county can test far higher.
- How many EPA Zone 1 counties are in District of Columbia?
- 0 of District of Columbia's 1 counties (0%) are EPA Zone 1 (highest potential), 0 are Zone 2 and 1 are Zone 3. The EPA zone map dates from 1993; the predicted values on this page come from a 2001-2021 model built on millions of actual tests, so the two can disagree for a given county.
- Should I test for radon in District of Columbia?
- Yes. Even though District of Columbia's predicted average is below 2 pCi/L, the EPA recommends every home be tested - radon varies house to house, and 0% of District of Columbia ZIP codes are still predicted at 2 pCi/L or higher.
District of Columbia radon program
District of Columbia's radon program page is at doee.dc.gov and, when we checked it, offered free radon test kits for District residents. The EPA also keeps a directory of every state radon contact: EPA state radon contacts page. Then read how to test and what mitigation costs.