2026 Rankings

EPA Radon Zone 1 ZIP Codes in Wisconsin - 2026

Last updated: August 31, 2026

396 ZIP codes ranked by Radon Zone #1: ZIP 53029 (Hartland, WI) - Zone 1 (highest potential)
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 in EPA Radon Zone 1 | All Wisconsin Rankings

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

100 Lowest-Ranked ZIP Codes

Rank ZIP Code City State Radon Zone Safety Score
1 53029 Hartland WI Zone 1 (highest potential) 33/100
2 53072 Pewaukee WI Zone 1 (highest potential) 33/100
3 53147 Lake Geneva WI Zone 1 (highest potential) 33/100
4 53186 Waukesha WI Zone 1 (highest potential) 33/100
5 53188 Waukesha WI Zone 1 (highest potential) 33/100
6 54474 Rothschild WI Zone 1 (highest potential) 45/100
7 54476 Schofield WI Zone 1 (highest potential) 47/100
8 53156 Palmyra WI Zone 1 (highest potential) 49/100
9 53089 Sussex WI Zone 1 (highest potential) 50/100
10 53114 Darien WI Zone 1 (highest potential) 50/100
11 53115 Delavan WI Zone 1 (highest potential) 50/100
12 53146 New Berlin WI Zone 1 (highest potential) 50/100
13 53189 Waukesha WI Zone 1 (highest potential) 50/100
14 53593 Verona WI Zone 1 (highest potential) 50/100
15 53597 Waunakee WI Zone 1 (highest potential) 50/100
16 53705 Madison WI Zone 1 (highest potential) 50/100
17 54235 Sturgeon Bay WI Zone 1 (highest potential) 50/100
18 54401 Wausau WI Zone 1 (highest potential) 50/100
19 54403 Wausau WI Zone 1 (highest potential) 50/100
20 53562 Middleton WI Zone 1 (highest potential) 52/100
21 53717 Madison WI Zone 1 (highest potential) 52/100
22 53528 Cross Plains WI Zone 1 (highest potential) 54/100
23 53066 Oconomowoc WI Zone 1 (highest potential) 60/100
24 53150 Muskego WI Zone 1 (highest potential) 60/100
25 53532 De Forest WI Zone 1 (highest potential) 60/100
26 53536 Evansville WI Zone 1 (highest potential) 60/100
27 53575 Oregon WI Zone 1 (highest potential) 60/100
28 53718 Madison WI Zone 1 (highest potential) 60/100
29 53032 Horicon WI Zone 1 (highest potential) 61/100
30 53045 Brookfield WI Zone 1 (highest potential) 61/100
31 53549 Jefferson WI Zone 1 (highest potential) 61/100
32 53719 Madison WI Zone 1 (highest potential) 61/100
33 53051 Menomonee Falls WI Zone 1 (highest potential) 62/100
34 53590 Sun Prairie WI Zone 1 (highest potential) 62/100
35 53704 Madison WI Zone 1 (highest potential) 62/100
36 53559 Marshall WI Zone 1 (highest potential) 63/100
37 53714 Madison WI Zone 1 (highest potential) 63/100
38 54971 Ripon WI Zone 1 (highest potential) 63/100
39 53005 Brookfield WI Zone 1 (highest potential) 64/100
40 53151 New Berlin WI Zone 1 (highest potential) 64/100
41 53534 Edgerton WI Zone 1 (highest potential) 64/100
42 53583 Sauk City WI Zone 1 (highest potential) 64/100
43 53598 Windsor WI Zone 1 (highest potential) 64/100
44 53711 Madison WI Zone 1 (highest potential) 64/100
45 53713 Madison WI Zone 1 (highest potential) 64/100
46 54455 Mosinee WI Zone 1 (highest potential) 64/100
47 54935 Fond Du Lac WI Zone 1 (highest potential) 64/100
48 54937 Fond Du Lac WI Zone 1 (highest potential) 64/100
49 53121 Elkhorn WI Zone 1 (highest potential) 65/100
50 53122 Elm Grove WI Zone 1 (highest potential) 65/100
51 53149 Mukwonago WI Zone 1 (highest potential) 65/100
52 53527 Cottage Grove WI Zone 1 (highest potential) 65/100
53 53538 Fort Atkinson WI Zone 1 (highest potential) 65/100
54 53548 Janesville WI Zone 1 (highest potential) 65/100
55 53558 Mc Farland WI Zone 1 (highest potential) 65/100
56 53703 Madison WI Zone 1 (highest potential) 65/100
57 53706 Madison WI Zone 1 (highest potential) 65/100
58 53715 Madison WI Zone 1 (highest potential) 65/100
59 53716 Madison WI Zone 1 (highest potential) 65/100
60 53726 Madison WI Zone 1 (highest potential) 65/100
61 53818 Platteville WI Zone 1 (highest potential) 65/100
62 53050 Mayville WI Zone 1 (highest potential) 66/100
63 53094 Watertown WI Zone 1 (highest potential) 66/100
64 53190 Whitewater WI Zone 1 (highest potential) 66/100
65 53511 Beloit WI Zone 1 (highest potential) 66/100
66 53525 Clinton WI Zone 1 (highest potential) 66/100
67 53545 Janesville WI Zone 1 (highest potential) 66/100
68 53551 Lake Mills WI Zone 1 (highest potential) 66/100
69 53589 Stoughton WI Zone 1 (highest potential) 66/100
70 53594 Waterloo WI Zone 1 (highest potential) 66/100
71 53813 Lancaster WI Zone 1 (highest potential) 66/100
72 53916 Beaver Dam WI Zone 1 (highest potential) 66/100
73 53963 Waupun WI Zone 1 (highest potential) 66/100
74 53120 East Troy WI Zone 1 (highest potential) 67/100
75 53546 Janesville WI Zone 1 (highest potential) 67/100
76 53563 Milton WI Zone 1 (highest potential) 67/100
77 53572 Mount Horeb WI Zone 1 (highest potential) 67/100
78 53002 Allenton WI Zone 1 (highest potential) —
79 53003 Ashippun WI Zone 1 (highest potential) —
80 53006 Brownsville WI Zone 1 (highest potential) —
81 53007 Butler WI Zone 1 (highest potential) —
82 53008 Brookfield WI Zone 1 (highest potential) —
83 53010 Campbellsport WI Zone 1 (highest potential) —
84 53011 Cascade WI Zone 1 (highest potential) —
85 53016 Clyman WI Zone 1 (highest potential) —
86 53017 Colgate WI Zone 1 (highest potential) —
87 53018 Delafield WI Zone 1 (highest potential) —
88 53019 Eden WI Zone 1 (highest potential) —
89 53022 Germantown WI Zone 1 (highest potential) —
90 53027 Hartford WI Zone 1 (highest potential) —
91 53034 Hustisford WI Zone 1 (highest potential) —
92 53035 Iron Ridge WI Zone 1 (highest potential) —
93 53036 Ixonia WI Zone 1 (highest potential) —
94 53037 Jackson WI Zone 1 (highest potential) —
95 53038 Johnson Creek WI Zone 1 (highest potential) —
96 53039 Juneau WI Zone 1 (highest potential) —
97 53040 Kewaskum WI Zone 1 (highest potential) —
98 53046 Lannon WI Zone 1 (highest potential) —
99 53047 Lebanon WI Zone 1 (highest potential) —
100 53048 Lomira WI Zone 1 (highest potential) —

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%.

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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