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	61523	Chillicothe	IL	Zone 1 (High)	39/100
2	60177	South Elgin	IL	Zone 1 (High)	40/100
3	61604	Peoria	IL	Zone 1 (High)	44/100
4	61536	Hanna City	IL	Zone 1 (High)	45/100
5	61547	Mapleton	IL	Zone 1 (High)	45/100
6	61607	Peoria	IL	Zone 1 (High)	45/100
7	61073	Roscoe	IL	Zone 1 (High)	47/100
8	61615	Peoria	IL	Zone 1 (High)	47/100
9	61072	Rockton	IL	Zone 1 (High)	48/100
10	61111	Loves Park	IL	Zone 1 (High)	48/100
11	61103	Rockford	IL	Zone 1 (High)	49/100
12	61115	Machesney Park	IL	Zone 1 (High)	49/100
13	61244	East Moline	IL	Zone 1 (High)	50/100
14	61265	Moline	IL	Zone 1 (High)	50/100
15	61282	Silvis	IL	Zone 1 (High)	50/100
16	61525	Dunlap	IL	Zone 1 (High)	50/100
17	61526	Edelstein	IL	Zone 1 (High)	50/100
18	61528	Edwards	IL	Zone 1 (High)	50/100
19	61552	Mossville	IL	Zone 1 (High)	50/100
20	61602	Peoria	IL	Zone 1 (High)	50/100
21	61603	Peoria	IL	Zone 1 (High)	50/100
22	61606	Peoria	IL	Zone 1 (High)	50/100
23	61614	Peoria	IL	Zone 1 (High)	50/100
24	61616	Peoria Heights	IL	Zone 1 (High)	50/100
25	61625	Peoria	IL	Zone 1 (High)	50/100
26	61704	Bloomington	IL	Zone 1 (High)	50/100
27	61705	Bloomington	IL	Zone 1 (High)	50/100
28	62712	Springfield	IL	Zone 1 (High)	50/100
29	61264	Milan	IL	Zone 1 (High)	52/100
30	60124	Elgin	IL	Zone 1 (High)	53/100
31	62563	Rochester	IL	Zone 1 (High)	53/100
32	60175	Saint Charles	IL	Zone 1 (High)	54/100
33	60140	Hampshire	IL	Zone 1 (High)	55/100
34	61240	Coal Valley	IL	Zone 1 (High)	56/100
35	61701	Bloomington	IL	Zone 1 (High)	57/100
36	60136	Gilberts	IL	Zone 1 (High)	58/100
37	61752	Le Roy	IL	Zone 1 (High)	58/100
38	62707	Springfield	IL	Zone 1 (High)	58/100
39	60120	Elgin	IL	Zone 1 (High)	59/100
40	60123	Elgin	IL	Zone 1 (High)	59/100
41	60174	Saint Charles	IL	Zone 1 (High)	59/100
42	61109	Rockford	IL	Zone 1 (High)	59/100
43	61016	Cherry Valley	IL	Zone 1 (High)	60/100
44	62521	Decatur	IL	Zone 1 (High)	60/100
45	62549	Mt Zion	IL	Zone 1 (High)	60/100
46	61102	Rockford	IL	Zone 1 (High)	61/100
47	61108	Rockford	IL	Zone 1 (High)	61/100
48	61112	Rockford	IL	Zone 1 (High)	61/100
49	61802	Urbana	IL	Zone 1 (High)	61/100
50	61925	Dalton City	IL	Zone 1 (High)	61/100
51	60119	Elburn	IL	Zone 1 (High)	62/100
52	60502	Aurora	IL	Zone 1 (High)	62/100
53	61201	Rock Island	IL	Zone 1 (High)	62/100
54	61822	Champaign	IL	Zone 1 (High)	62/100
55	61874	Savoy	IL	Zone 1 (High)	62/100
56	62704	Springfield	IL	Zone 1 (High)	62/100
57	62711	Springfield	IL	Zone 1 (High)	62/100
58	60203	Evanston	IL	Zone 1 (High)	63/100
59	60510	Batavia	IL	Zone 1 (High)	63/100
60	61036	Galena	IL	Zone 1 (High)	63/100
61	61801	Urbana	IL	Zone 1 (High)	63/100
62	60134	Geneva	IL	Zone 1 (High)	64/100
63	60183	Wasco	IL	Zone 1 (High)	64/100
64	60505	Aurora	IL	Zone 1 (High)	64/100
65	61284	Taylor Ridge	IL	Zone 1 (High)	64/100
66	61820	Champaign	IL	Zone 1 (High)	64/100
67	62035	Godfrey	IL	Zone 1 (High)	64/100
68	62052	Jerseyville	IL	Zone 1 (High)	64/100
69	62301	Quincy	IL	Zone 1 (High)	64/100
70	62305	Quincy	IL	Zone 1 (High)	64/100
71	62526	Decatur	IL	Zone 1 (High)	64/100
72	60504	Aurora	IL	Zone 1 (High)	65/100
73	60542	North Aurora	IL	Zone 1 (High)	65/100
74	60554	Sugar Grove	IL	Zone 1 (High)	65/100
75	61080	South Beloit	IL	Zone 1 (High)	65/100
76	61853	Mahomet	IL	Zone 1 (High)	65/100
77	61863	Pesotum	IL	Zone 1 (High)	65/100
78	61866	Rantoul	IL	Zone 1 (High)	65/100
79	61880	Tolono	IL	Zone 1 (High)	65/100
80	62338	Fowler	IL	Zone 1 (High)	65/100
81	62360	Payson	IL	Zone 1 (High)	65/100
82	62522	Decatur	IL	Zone 1 (High)	65/100
83	62561	Riverton	IL	Zone 1 (High)	65/100
84	62615	Auburn	IL	Zone 1 (High)	65/100
85	62684	Sherman	IL	Zone 1 (High)	65/100
86	62703	Springfield	IL	Zone 1 (High)	65/100
87	60110	Carpentersville	IL	Zone 1 (High)	66/100
88	60506	Aurora	IL	Zone 1 (High)	66/100
89	60538	Montgomery	IL	Zone 1 (High)	66/100
90	61041	Hanover	IL	Zone 1 (High)	66/100
91	61101	Rockford	IL	Zone 1 (High)	66/100
92	61107	Rockford	IL	Zone 1 (High)	66/100
93	61114	Rockford	IL	Zone 1 (High)	66/100
94	61761	Normal	IL	Zone 1 (High)	66/100
95	62022	Dow	IL	Zone 1 (High)	66/100
96	62031	Fieldon	IL	Zone 1 (High)	66/100
97	62037	Grafton	IL	Zone 1 (High)	66/100
98	62320	Camp Point	IL	Zone 1 (High)	66/100
99	62501	Argenta	IL	Zone 1 (High)	66/100
100	62523	Decatur	IL	Zone 1 (High)	66/100

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: 2026-08-14.

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%.