ZIP Codes in EPA Radon Zone 1 - 2026

Out of 14,079 ZIP codes with data across all 50 states, these are the lowest-ranked areas for radon zone. Each ZIP links to a full safety report with water quality, lead, radon, and flood data.

Statistic	Value
ZIP codes ranked	14,079
Lowest value	Zone 1 (highest potential)
Median value	Zone 1 (highest potential)

100 Lowest-Ranked ZIP Codes

Rank	ZIP Code	City	State	Radon Zone	Safety Score
1	43137	Lockbourne	OH	Zone 1 (highest potential)	25/100
2	43207	Columbus	OH	Zone 1 (highest potential)	25/100
3	15108	Coraopolis	PA	Zone 1 (highest potential)	27/100
4	43119	Galloway	OH	Zone 1 (highest potential)	28/100
5	80550	Windsor	CO	Zone 1 (highest potential)	31/100
6	43123	Grove City	OH	Zone 1 (highest potential)	32/100
7	43125	Groveport	OH	Zone 1 (highest potential)	32/100
8	02874	Saunderstown	RI	Zone 1 (highest potential)	33/100
9	02879	Wakefield	RI	Zone 1 (highest potential)	33/100
10	02881	Kingston	RI	Zone 1 (highest potential)	33/100
11	02892	West Kingston	RI	Zone 1 (highest potential)	33/100
12	06482	Sandy Hook	CT	Zone 1 (highest potential)	33/100
13	06488	Southbury	CT	Zone 1 (highest potential)	33/100
14	06804	Brookfield	CT	Zone 1 (highest potential)	33/100
15	06810	Danbury	CT	Zone 1 (highest potential)	33/100
16	06811	Danbury	CT	Zone 1 (highest potential)	33/100
17	07005	Boonton	NJ	Zone 1 (highest potential)	33/100
18	07734	Keansburg	NJ	Zone 1 (highest potential)	33/100
19	07748	Middletown	NJ	Zone 1 (highest potential)	33/100
20	07801	Dover	NJ	Zone 1 (highest potential)	33/100
21	07828	Budd Lake	NJ	Zone 1 (highest potential)	33/100
22	07834	Denville	NJ	Zone 1 (highest potential)	33/100
23	07836	Flanders	NJ	Zone 1 (highest potential)	33/100
24	07840	Hackettstown	NJ	Zone 1 (highest potential)	33/100
25	07853	Long Valley	NJ	Zone 1 (highest potential)	33/100
26	07866	Rockaway	NJ	Zone 1 (highest potential)	33/100
27	07885	Wharton	NJ	Zone 1 (highest potential)	33/100
28	08501	Allentown	NJ	Zone 1 (highest potential)	33/100
29	08560	Titusville	NJ	Zone 1 (highest potential)	33/100
30	08618	Trenton	NJ	Zone 1 (highest potential)	33/100
31	08619	Trenton	NJ	Zone 1 (highest potential)	33/100
32	08628	Trenton	NJ	Zone 1 (highest potential)	33/100
33	08648	Lawrence Township	NJ	Zone 1 (highest potential)	33/100
34	08690	Trenton	NJ	Zone 1 (highest potential)	33/100
35	08691	Trenton	NJ	Zone 1 (highest potential)	33/100
36	08822	Flemington	NJ	Zone 1 (highest potential)	33/100
37	08826	Glen Gardner	NJ	Zone 1 (highest potential)	33/100
38	10950	Monroe	NY	Zone 1 (highest potential)	33/100
39	12186	Voorheesville	NY	Zone 1 (highest potential)	33/100
40	15009	Beaver	PA	Zone 1 (highest potential)	33/100
41	15059	Midland	PA	Zone 1 (highest potential)	33/100
42	15061	Monaca	PA	Zone 1 (highest potential)	33/100
43	15650	Latrobe	PA	Zone 1 (highest potential)	33/100
44	16823	Bellefonte	PA	Zone 1 (highest potential)	33/100
45	17013	Carlisle	PA	Zone 1 (highest potential)	33/100
46	17015	Carlisle	PA	Zone 1 (highest potential)	33/100
47	17340	Littlestown	PA	Zone 1 (highest potential)	33/100
48	17702	Williamsport	PA	Zone 1 (highest potential)	33/100
49	17754	Montoursville	PA	Zone 1 (highest potential)	33/100
50	18041	East Greenville	PA	Zone 1 (highest potential)	33/100
51	18049	Emmaus	PA	Zone 1 (highest potential)	33/100
52	18062	Macungie	PA	Zone 1 (highest potential)	33/100
53	18070	Palm	PA	Zone 1 (highest potential)	33/100
54	18076	Red Hill	PA	Zone 1 (highest potential)	33/100
55	18902	Doylestown	PA	Zone 1 (highest potential)	33/100
56	18914	Chalfont	PA	Zone 1 (highest potential)	33/100
57	18938	New Hope	PA	Zone 1 (highest potential)	33/100
58	18940	Newtown	PA	Zone 1 (highest potential)	33/100
59	18944	Perkasie	PA	Zone 1 (highest potential)	33/100
60	18951	Quakertown	PA	Zone 1 (highest potential)	33/100
61	18954	Richboro	PA	Zone 1 (highest potential)	33/100
62	18960	Sellersville	PA	Zone 1 (highest potential)	33/100
63	18966	Southampton	PA	Zone 1 (highest potential)	33/100
64	18974	Warminster	PA	Zone 1 (highest potential)	33/100
65	19002	Ambler	PA	Zone 1 (highest potential)	33/100
66	19025	Dresher	PA	Zone 1 (highest potential)	33/100
67	19034	Fort Washington	PA	Zone 1 (highest potential)	33/100
68	19040	Hatboro	PA	Zone 1 (highest potential)	33/100
69	19044	Horsham	PA	Zone 1 (highest potential)	33/100
70	19053	Feasterville Trevose	PA	Zone 1 (highest potential)	33/100
71	19067	Morrisville	PA	Zone 1 (highest potential)	33/100
72	19090	Willow Grove	PA	Zone 1 (highest potential)	33/100
73	19317	Chadds Ford	PA	Zone 1 (highest potential)	33/100
74	19335	Downingtown	PA	Zone 1 (highest potential)	33/100
75	19344	Honey Brook	PA	Zone 1 (highest potential)	33/100
76	19348	Kennett Square	PA	Zone 1 (highest potential)	33/100
77	19380	West Chester	PA	Zone 1 (highest potential)	33/100
78	19382	West Chester	PA	Zone 1 (highest potential)	33/100
79	19383	West Chester	PA	Zone 1 (highest potential)	33/100
80	19403	Norristown	PA	Zone 1 (highest potential)	33/100
81	19422	Blue Bell	PA	Zone 1 (highest potential)	33/100
82	19426	Collegeville	PA	Zone 1 (highest potential)	33/100
83	19454	North Wales	PA	Zone 1 (highest potential)	33/100
84	19460	Phoenixville	PA	Zone 1 (highest potential)	33/100
85	26034	Chester	WV	Zone 1 (highest potential)	33/100
86	26062	Weirton	WV	Zone 1 (highest potential)	33/100
87	26070	Wellsburg	WV	Zone 1 (highest potential)	33/100
88	35773	Toney	AL	Zone 1 (highest potential)	33/100
89	37012	Alexandria	TN	Zone 1 (highest potential)	33/100
90	43912	Bridgeport	OH	Zone 1 (highest potential)	33/100
91	43935	Martins Ferry	OH	Zone 1 (highest potential)	33/100
92	43950	Saint Clairsville	OH	Zone 1 (highest potential)	33/100
93	45011	Hamilton	OH	Zone 1 (highest potential)	33/100
94	46614	South Bend	IN	Zone 1 (highest potential)	33/100
95	53029	Hartland	WI	Zone 1 (highest potential)	33/100
96	53072	Pewaukee	WI	Zone 1 (highest potential)	33/100
97	53147	Lake Geneva	WI	Zone 1 (highest potential)	33/100
98	53186	Waukesha	WI	Zone 1 (highest potential)	33/100
99	53188	Waukesha	WI	Zone 1 (highest potential)	33/100
100	80260	Denver	CO	Zone 1 (highest potential)	33/100

Rankings by State

State	ZIP Codes Ranked
Pennsylvania	1,596
New York	1,161
Iowa	1,056
Ohio	909
Illinois	797
Minnesota	731
Indiana	635
Colorado	602
Virginia	487
Nebraska	445
Maine	403
North Dakota	400
Wisconsin	396
Kansas	396
Montana	355
Tennessee	332
South Dakota	282
Maryland	277
Massachusetts	269
Kentucky	249
New Jersey	246
West Virginia	230
Connecticut	216
Missouri	201
Wyoming	185
New Mexico	153
Alabama	151
Georgia	147
Idaho	145
Washington	133
Michigan	133
California	86
North Carolina	80
Utah	62
Nevada	38
Rhode Island	33
New Hampshire	32
South Carolina	30

Methodology

This ranking is limited to EPA county-level radon zone classification. Zone 1 identifies the highest county-level potential category; it does not measure a home or establish whether any building is above an action level. Within Zone 1, ZIP codes are sub-ranked by Home Safety Score to organize area context.

Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-08-31.

Frequently Asked Questions

What is EPA Radon Zone 1?

Zone 1 is the EPA highest county-level radon-potential category. It is not a measurement for a home and cannot determine whether a building is above an action level. A home test is required for that decision.

Should I test for radon?

The EPA recommends testing all homes regardless of radon zone. A DIY test kit costs $15-40. Professional testing costs $150-250. If levels exceed 4 pCi/L, mitigation systems ($800-2,500) can reduce radon by up to 99%.