Highest Radon Risk ZIP Codes in Illinois — 2026

Out of 797 ZIP codes with data in Illinois, these are the lowest-ranked areas for radon zone. See also: National ZIP Codes with Highest Radon Risk | All Illinois Rankings

Statistic	Value
ZIP codes ranked	797
Lowest value	Zone 1 (High)
Median value	Zone 1 (High)
State	Illinois

100 Lowest-Ranked ZIP Codes

Rank	ZIP Code	City	State	Radon Zone	Safety Score
1	61484	Vermont	IL	Zone 1 (High)	13/100
2	61604	Peoria	IL	Zone 1 (High)	22/100
3	61614	Peoria	IL	Zone 1 (High)	22/100
4	61615	Peoria	IL	Zone 1 (High)	22/100
5	61450	La Harpe	IL	Zone 1 (High)	23/100
6	61625	Peoria	IL	Zone 1 (High)	23/100
7	61629	Peoria	IL	Zone 1 (High)	23/100
8	61630	Peoria	IL	Zone 1 (High)	23/100
9	61633	Peoria	IL	Zone 1 (High)	23/100
10	61634	Peoria	IL	Zone 1 (High)	23/100
11	61636	Peoria	IL	Zone 1 (High)	23/100
12	61637	Peoria	IL	Zone 1 (High)	23/100
13	61638	Peoria	IL	Zone 1 (High)	23/100
14	61639	Peoria	IL	Zone 1 (High)	23/100
15	61641	Peoria	IL	Zone 1 (High)	23/100
16	61643	Peoria	IL	Zone 1 (High)	23/100
17	61651	Peoria	IL	Zone 1 (High)	23/100
18	61654	Peoria	IL	Zone 1 (High)	23/100
19	61656	Peoria	IL	Zone 1 (High)	23/100
20	60934	Emington	IL	Zone 1 (High)	24/100
21	60505	Aurora	IL	Zone 1 (High)	25/100
22	61244	East Moline	IL	Zone 1 (High)	26/100
23	61262	Lynn Center	IL	Zone 1 (High)	27/100
24	60121	Elgin	IL	Zone 1 (High)	28/100
25	60568	Aurora	IL	Zone 1 (High)	28/100
26	60572	Aurora	IL	Zone 1 (High)	28/100
27	60930	Danforth	IL	Zone 1 (High)	28/100
28	61104	Rockford	IL	Zone 1 (High)	28/100
29	61773	Sibley	IL	Zone 1 (High)	28/100
30	62666	Middletown	IL	Zone 1 (High)	28/100
31	61378	West Brooklyn	IL	Zone 1 (High)	29/100
32	62349	Loraine	IL	Zone 1 (High)	29/100
33	62520	Dawson	IL	Zone 1 (High)	29/100
34	60506	Aurora	IL	Zone 1 (High)	30/100
35	60120	Elgin	IL	Zone 1 (High)	31/100
36	61070	Rock City	IL	Zone 1 (High)	31/100
37	61106	Rockford	IL	Zone 1 (High)	31/100
38	61112	Rockford	IL	Zone 1 (High)	31/100
39	61125	Rockford	IL	Zone 1 (High)	31/100
40	61126	Rockford	IL	Zone 1 (High)	31/100
41	61078	Shannon	IL	Zone 1 (High)	32/100
42	61602	Peoria	IL	Zone 1 (High)	32/100
43	61603	Peoria	IL	Zone 1 (High)	32/100
44	61607	Peoria	IL	Zone 1 (High)	32/100
45	61870	Ridge Farm	IL	Zone 1 (High)	32/100
46	61102	Rockford	IL	Zone 1 (High)	33/100
47	61103	Rockford	IL	Zone 1 (High)	33/100
48	61107	Rockford	IL	Zone 1 (High)	33/100
49	61108	Rockford	IL	Zone 1 (High)	33/100
50	61109	Rockford	IL	Zone 1 (High)	33/100
51	61771	Secor	IL	Zone 1 (High)	33/100
52	62326	Colchester	IL	Zone 1 (High)	33/100
53	61720	Anchor	IL	Zone 1 (High)	34/100
54	60502	Aurora	IL	Zone 1 (High)	35/100
55	60962	Roberts	IL	Zone 1 (High)	35/100
56	61425	Carman	IL	Zone 1 (High)	35/100
57	61543	Liverpool	IL	Zone 1 (High)	35/100
58	62037	Grafton	IL	Zone 1 (High)	35/100
59	62617	Bath	IL	Zone 1 (High)	35/100
60	60123	Elgin	IL	Zone 1 (High)	36/100
61	60912	Beaverville	IL	Zone 1 (High)	36/100
62	61356	Princeton	IL	Zone 1 (High)	36/100
63	61601	Peoria	IL	Zone 1 (High)	37/100
64	61605	Peoria	IL	Zone 1 (High)	37/100
65	61606	Peoria	IL	Zone 1 (High)	37/100
66	61612	Peoria	IL	Zone 1 (High)	37/100
67	61613	Peoria	IL	Zone 1 (High)	37/100
68	61650	Peoria	IL	Zone 1 (High)	37/100
69	61652	Peoria	IL	Zone 1 (High)	37/100
70	61653	Peoria	IL	Zone 1 (High)	37/100
71	61655	Peoria	IL	Zone 1 (High)	37/100
72	61917	Brocton	IL	Zone 1 (High)	37/100
73	62341	Hamilton	IL	Zone 1 (High)	37/100
74	61101	Rockford	IL	Zone 1 (High)	38/100
75	61114	Rockford	IL	Zone 1 (High)	38/100
76	61752	Le Roy	IL	Zone 1 (High)	38/100
77	61616	Peoria Heights	IL	Zone 1 (High)	39/100
78	60111	Clare	IL	Zone 1 (High)	40/100
79	60129	Esmond	IL	Zone 1 (High)	40/100
80	60144	Kaneville	IL	Zone 1 (High)	40/100
81	60147	Lafox	IL	Zone 1 (High)	40/100
82	60504	Aurora	IL	Zone 1 (High)	40/100
83	60507	Aurora	IL	Zone 1 (High)	40/100
84	60519	Eola	IL	Zone 1 (High)	40/100
85	60542	North Aurora	IL	Zone 1 (High)	40/100
86	60926	Claytonville	IL	Zone 1 (High)	40/100
87	60939	Goodwine	IL	Zone 1 (High)	40/100
88	60945	Iroquois	IL	Zone 1 (High)	40/100
89	60956	Papineau	IL	Zone 1 (High)	40/100
90	60967	Stockland	IL	Zone 1 (High)	40/100
91	61007	Baileyville	IL	Zone 1 (High)	40/100
92	61011	Caledonia	IL	Zone 1 (High)	40/100
93	61015	Chana	IL	Zone 1 (High)	40/100
94	61027	Eleroy	IL	Zone 1 (High)	40/100
95	61037	Galt	IL	Zone 1 (High)	40/100
96	61043	Holcomb	IL	Zone 1 (High)	40/100
97	61044	Kent	IL	Zone 1 (High)	40/100
98	61059	Nora	IL	Zone 1 (High)	40/100
99	61077	Seward	IL	Zone 1 (High)	40/100
100	61091	Woosung	IL	Zone 1 (High)	40/100

Methodology

Radon rankings are based on EPA county-level radon zone classifications. Zone 1 (highest risk) has predicted average indoor radon levels above 4 pCi/L — the EPA action level. Zone 2 is moderate (2-4 pCi/L) and Zone 3 is low (below 2 pCi/L). Within Zone 1, ZIP codes are sub-ranked by Home Safety Score to prioritize areas with compounding risk factors.

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: 2026-06-04.

Frequently Asked Questions

What is EPA Radon Zone 1?

Zone 1 is the EPA highest-risk classification, meaning the county has predicted average indoor radon levels above 4 pCi/L — the level at which the EPA recommends mitigation. Radon causes about 21,000 lung cancer deaths per year in the U.S.

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%.