Radon Zones Map
The U.S. Environmental Protection Agency (EPA) created this map to identify areas with the potential
for elevated indoor radon levels. The EPA Map of Radon Zones helps national, state, and local
organizations implement radon-resistant building codes. The map should not be used to determine if a
home in a given zone should be tested for radon. Homes with elevated levels of radon have been found
in all three zones. All homes should be tested for radon.
EPA Map of Radon Zones
The purpose otthtsmaplsto assist National, Stab, and local organizations to target their
resoutves and to Implement radon-isslstontbutding codes. Thts map is not Intended to be used
to dernmne fa borne ma given zone should be tested forttdon. Homes wtti eleiaed levels
of radon have been found tn altm anas. At homes should be testBd wattless of
geographic kxatran
IMPORTANT Consult the EPA Map of Radon Zones dtxument (EPA -*02-R-iWTI) before usiifl this map. This document oontaim Information on radon potential
variations vMn counties. EPA also mxmrends that this map be supptetmnted wifa any available beat data Holder b flutter understand and prated
Ire radon potential of a spectic ma.
Guam - Prefmmary Zone designation
What do the colors mean?
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Zone 1 (red zones)
Highest potential; average indoor radon levels may be
greater than 4 pCi/L (picocuries per liter)
Zone 2 (orange zones)
Moderate potential; average indoor radon levels may be
between 2 and 4 pCi/L

Zone 3 (yellow zones)
Low potential; average indoor radon levels may be less than 2
pCi/L

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