Radon in Hawaii: radon map by county
EPA's Map of Radon Zones puts 0 of Hawaii's 5 counties in Zone 1 (predicted average indoor radon above 4 pCi/L), 0 in Zone 2 and 5 in Zone 3.
Radon by county in Hawaii
| County | EPA zone | Lab tests | Median | 4+ pCi/L |
|---|---|---|---|---|
| Hawaii County | Zone 3 | n/a | n/a | n/a |
| Honolulu County | Zone 3 | n/a | n/a | n/a |
| Kalawao County | Zone 3 | n/a | n/a | n/a |
| Kauai County | Zone 3 | n/a | n/a | n/a |
| Maui County | Zone 3 | n/a | n/a | n/a |
Lab tests: buildings tested by radon laboratories, 2008 to 2017; median in pCi/L; “4+ pCi/L” is the share of tests at or above EPA's action level. n/a: no value on file (no tests, or too few to report).
What the zones mean
Zone 1 counties have a predicted average indoor radon screening level above 4 pCi/L, Zone 2 from 2 to 4 pCi/L and Zone 3 below 2 pCi/L. The prediction is from 1993 indoor measurements, geology, aerial radioactivity, soils and foundation types. EPA: “This map should not be used to determine if individual homes need to be tested.” EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of exposure.
Radon in Hawaii: questions
What radon zone is Hawaii?
EPA's 1993 map does not give states one zone; it zones each county. In Hawaii, 0 counties are Zone 1, 0 Zone 2 and 5 Zone 3. EPA says the map "should not be used to determine if individual homes need to be tested".
Should I test for radon in Hawaii?
Yes. EPA recommends testing every home no matter where it is, fixing it at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of radon exposure.
Other states in EPA Region 9
Other free hazard lookups
- Radon by county and ZIP codeEPA radon zone and the radon test results on file for any county, ZIP code or address.
- Fault lines near an addressUSGS-mapped earthquake faults within 5 miles, their age and slip rate, and the USGS seismic hazard value.
- Power lines near an addressHigh-voltage transmission lines within 1 mile from federal maps, with voltage and distance.
- Flood zone lookupThe FEMA flood zone mapped at any US address. Not an official flood zone determination.
- Superfund sites near an addressThe nearest EPA Superfund (NPL) sites and their status.
All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).
Superfund sites in Hawaii · Radon map of every state
Data compiled 2026-10-20. County-level screening information, not a radon measurement of any building.