2026 Rankings

Highest Radon Risk ZIP Codes in Wisconsin — 2026

Last updated: June 4, 2026

396 ZIP codes ranked by Radon Zone #1: ZIP 53039 (Juneau, WI) — Zone 1 (High)
Lead Violations Lowest Score Safest Flood Risk Energy Cost Radon PFAS Reliability EJ Index Homebuyer Risk CO & Gas Safest Gas Remediation Burden Unresolved Violations (by Utility) Water Equity (by Utility)

Out of 396 ZIP codes with data in Wisconsin, these are the lowest-ranked areas for radon zone. See also: National ZIP Codes with Highest Radon Risk | All Wisconsin Rankings

Statistic Value
ZIP codes ranked 396
Lowest value Zone 1 (High)
Median value Zone 1 (High)
State Wisconsin

100 Lowest-Ranked ZIP Codes

Rank ZIP Code City State Radon Zone Safety Score
1 53039 Juneau WI Zone 1 (High) 24/100
2 53094 Watertown WI Zone 1 (High) 28/100
3 53098 Watertown WI Zone 1 (High) 28/100
4 54645 Mount Sterling WI Zone 1 (High) 28/100
5 54404 Marshfield WI Zone 1 (High) 32/100
6 54472 Marshfield WI Zone 1 (High) 32/100
7 53538 Fort Atkinson WI Zone 1 (High) 34/100
8 53187 Waukesha WI Zone 1 (High) 36/100
9 53047 Lebanon WI Zone 1 (High) 40/100
10 53056 Merton WI Zone 1 (High) 40/100
11 53059 Neosho WI Zone 1 (High) 40/100
12 53072 Pewaukee WI Zone 1 (High) 40/100
13 53078 Rubicon WI Zone 1 (High) 40/100
14 53079 Saint Cloud WI Zone 1 (High) 40/100
15 53099 Woodland WI Zone 1 (High) 40/100
16 53127 Genesee Depot WI Zone 1 (High) 40/100
17 53137 Helenville WI Zone 1 (High) 40/100
18 53195 Zenda WI Zone 1 (High) 40/100
19 53235 Saint Francis WI Zone 1 (High) 40/100
20 53505 Avalon WI Zone 1 (High) 40/100
21 53542 Hanover WI Zone 1 (High) 40/100
22 53549 Jefferson WI Zone 1 (High) 40/100
23 53550 Juda WI Zone 1 (High) 40/100
24 53599 Woodford WI Zone 1 (High) 40/100
25 53827 Woodman WI Zone 1 (High) 40/100
26 53939 Kingston WI Zone 1 (High) 40/100
27 53942 Lime Ridge WI Zone 1 (High) 40/100
28 53956 Randolph WI Zone 1 (High) 40/100
29 53957 Randolph WI Zone 1 (High) 40/100
30 54010 East Ellsworth WI Zone 1 (High) 40/100
31 54135 Keshena WI Zone 1 (High) 40/100
32 54150 Neopit WI Zone 1 (High) 40/100
33 54182 Zachow WI Zone 1 (High) 40/100
34 54204 Brussels WI Zone 1 (High) 40/100
35 54211 Ephraim WI Zone 1 (High) 40/100
36 54407 Amherst Junction WI Zone 1 (High) 40/100
37 54408 Aniwa WI Zone 1 (High) 40/100
38 54413 Babcock WI Zone 1 (High) 40/100
39 54415 Blenker WI Zone 1 (High) 40/100
40 54417 Brokaw WI Zone 1 (High) 40/100
41 54418 Bryant WI Zone 1 (High) 40/100
42 54423 Custer WI Zone 1 (High) 40/100
43 54424 Deerbrook WI Zone 1 (High) 40/100
44 54427 Eland WI Zone 1 (High) 40/100
45 54429 Elderon WI Zone 1 (High) 40/100
46 54430 Elton WI Zone 1 (High) 40/100
47 54432 Galloway WI Zone 1 (High) 40/100
48 54458 Nelsonville WI Zone 1 (High) 40/100
49 54462 Pearson WI Zone 1 (High) 40/100
50 54463 Pelican Lake WI Zone 1 (High) 40/100
51 54464 Phlox WI Zone 1 (High) 40/100
52 54471 Ringle WI Zone 1 (High) 40/100
53 54475 Rudolph WI Zone 1 (High) 40/100
54 54485 Summit Lake WI Zone 1 (High) 40/100
55 54640 Lynxville WI Zone 1 (High) 40/100
56 54721 Arkansaw WI Zone 1 (High) 40/100
57 54743 Gilmanton WI Zone 1 (High) 40/100
58 54926 Big Falls WI Zone 1 (High) 40/100
59 54928 Caroline WI Zone 1 (High) 40/100
60 54932 Eldorado WI Zone 1 (High) 40/100
61 54960 Neshkoro WI Zone 1 (High) 40/100
62 54961 New London WI Zone 1 (High) 40/100
63 54962 Ogdensburg WI Zone 1 (High) 40/100
64 54964 Pickett WI Zone 1 (High) 40/100
65 54974 Rosendale WI Zone 1 (High) 40/100
66 54977 Scandinavia WI Zone 1 (High) 40/100
67 54978 Tilleda WI Zone 1 (High) 40/100
68 54979 Van Dyne WI Zone 1 (High) 40/100
69 53121 Elkhorn WI Zone 1 (High) 41/100
70 53186 Waukesha WI Zone 1 (High) 41/100
71 53188 Waukesha WI Zone 1 (High) 41/100
72 54945 Iola WI Zone 1 (High) 41/100
73 54990 Iola WI Zone 1 (High) 41/100
74 54411 Athens WI Zone 1 (High) 42/100
75 54482 Stevens Point WI Zone 1 (High) 42/100
76 54492 Stevens Point WI Zone 1 (High) 42/100
77 54935 Fond Du Lac WI Zone 1 (High) 42/100
78 53534 Edgerton WI Zone 1 (High) 43/100
79 53565 Mineral Point WI Zone 1 (High) 43/100
80 54449 Marshfield WI Zone 1 (High) 44/100
81 54971 Ripon WI Zone 1 (High) 44/100
82 53532 De Forest WI Zone 1 (High) 45/100
83 54624 De Soto WI Zone 1 (High) 45/100
84 54657 Steuben WI Zone 1 (High) 45/100
85 54769 Stockholm WI Zone 1 (High) 45/100
86 54940 Fremont WI Zone 1 (High) 45/100
87 53189 Waukesha WI Zone 1 (High) 46/100
88 53581 Richland Center WI Zone 1 (High) 46/100
89 54481 Stevens Point WI Zone 1 (High) 46/100
90 53545 Janesville WI Zone 1 (High) 47/100
91 54937 Fond Du Lac WI Zone 1 (High) 47/100
92 53029 Hartland WI Zone 1 (High) 48/100
93 53184 Walworth WI Zone 1 (High) 49/100
94 53547 Janesville WI Zone 1 (High) 49/100
95 54936 Fond Du Lac WI Zone 1 (High) 49/100
96 53090 West Bend WI Zone 1 (High) 51/100
97 53095 West Bend WI Zone 1 (High) 51/100
98 53190 Whitewater WI Zone 1 (High) 51/100
99 53115 Delavan WI Zone 1 (High) 52/100
100 53546 Janesville WI Zone 1 (High) 52/100

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%.

Explore More Rankings

How this ranking is calculated, data sources, and limitations: Rankings Methodology →

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Disclaimer: Rankings are based on EPA, FEMA, and federal agency data. They reflect historical patterns and risk indicators, not necessarily current conditions. For the most current information, contact your local water utility or request a Consumer Confidence Report.

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