2026 Rankings

ZIP Codes with Most EPA Violations in Wisconsin — 2026

Last updated: August 31, 2026

372 ZIP codes ranked by Recorded EPA Violations #1: ZIP 53072 (Pewaukee, WI) - 142
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 372 ZIP codes with data in Wisconsin, these are the highest-ranked areas for recorded epa violations. See also: National ZIP Codes with Most EPA Water Violations | All Wisconsin Rankings

Statistic Value
ZIP codes ranked 372
Highest value 142
Median value 4
State Wisconsin

Top 100 Worst ZIP Codes

Rank ZIP Code City State Recorded EPA Violations Safety Score
1 53072 Pewaukee WI 142 33/100
2 53188 Waukesha WI 133 33/100
3 53186 Waukesha WI 97 33/100
4 53189 Waukesha WI 79 50/100
5 53146 New Berlin WI 76 50/100
6 53183 Wales WI 76 —
7 53095 West Bend WI 71 —
8 53115 Delavan WI 69 50/100
9 53040 Kewaskum WI 67 —
10 53147 Lake Geneva WI 63 33/100
11 53090 West Bend WI 62 —
12 53029 Hartland WI 50 33/100
13 54981 Waupaca WI 49 —
14 53105 Burlington WI 46 67/100
15 54983 Weyauwega WI 46 —
16 53128 Genoa City WI 43 —
17 53089 Sussex WI 42 50/100
18 53597 Waunakee WI 42 50/100
19 53114 Darien WI 40 50/100
20 53585 Sharon WI 40 —
21 53705 Madison WI 37 50/100
22 53593 Verona WI 36 50/100
23 54082 Houlton WI 34 —
24 53092 Thiensville WI 33 67/100
25 53403 Racine WI 32 69/100
26 53528 Cross Plains WI 32 54/100
27 53562 Middleton WI 32 52/100
28 53717 Madison WI 32 52/100
29 53406 Racine WI 31 67/100
30 54016 Hudson WI 31 —
31 54601 La Crosse WI 30 57/100
32 53807 Cuba City WI 27 —
33 53018 Delafield WI 26 —
34 53058 Nashotah WI 23 —
35 53820 Potosi WI 23 —
36 54868 Rice Lake WI 23 —
37 53045 Brookfield WI 22 61/100
38 53184 Walworth WI 22 —
39 53811 Hazel Green WI 22 —
40 54812 Barron WI 22 —
41 54829 Cumberland WI 22 —
42 54130 Kaukauna WI 20 74/100
43 53549 Jefferson WI 19 61/100
44 53125 Fontana WI 18 —
45 53402 Racine WI 18 73/100
46 53217 Milwaukee WI 17 67/100
47 54915 Appleton WI 17 —
48 53211 Milwaukee WI 16 67/100
49 54405 Abbotsford WI 16 —
50 54421 Colby WI 16 —
51 54425 Dorchester WI 16 —
52 54904 Oshkosh WI 15 —
53 53536 Evansville WI 13 60/100
54 54806 Ashland WI 13 80/100
55 54850 La Pointe WI 13 —
56 53038 Johnson Creek WI 12 —
57 53954 Pardeeville WI 12 —
58 54963 Omro WI 12 —
59 53137 Helenville WI 11 —
60 53925 Columbus WI 11 80/100
61 54603 La Crosse WI 11 60/100
62 54729 Chippewa Falls WI 11 —
63 53051 Menomonee Falls WI 10 62/100
64 53066 Oconomowoc WI 10 60/100
65 53168 Salem WI 10 —
66 53532 De Forest WI 10 60/100
67 53538 Fort Atkinson WI 10 65/100
68 53901 Portage WI 10 77/100
69 54155 Oneida WI 10 79/100
70 54311 Green Bay WI 10 80/100
71 54313 Green Bay WI 10 79/100
72 54703 Eau Claire WI 10 58/100
73 54913 Appleton WI 10 80/100
74 54952 Menasha WI 10 —
75 54986 Winneconne WI 10 —
76 53076 Richfield WI 9 —
77 53177 Sturtevant WI 9 79/100
78 53191 Williams Bay WI 9 —
79 53575 Oregon WI 9 60/100
80 53719 Madison WI 9 61/100
81 54005 Clear Lake WI 9 —
82 54115 De Pere WI 9 80/100
83 54409 Antigo WI 9 —
84 54426 Edgar WI 9 —
85 54558 Saint Germain WI 9 —
86 54562 Three Lakes WI 9 —
87 54935 Fond Du Lac WI 9 64/100
88 54937 Fond Du Lac WI 9 64/100
89 53005 Brookfield WI 8 64/100
90 53704 Madison WI 8 62/100
91 53714 Madison WI 8 63/100
92 53718 Madison WI 8 60/100
93 53916 Beaver Dam WI 8 66/100
94 53956 Randolph WI 8 —
95 54129 Hilbert WI 8 —
96 54650 Onalaska WI 8 78/100
97 53075 Random Lake WI 7 —
98 53150 Muskego WI 7 60/100
99 53523 Cambridge WI 7 —
100 53578 Prairie Du Sac WI 7 78/100

Methodology

Violation counts include all types recorded in the EPA SDWIS database: Maximum Contaminant Level (MCL) violations, treatment technique violations, and monitoring/reporting violations. Both resolved and unresolved violations are counted. Higher counts may reflect longer system histories or larger service areas.

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 counts as an EPA water violation?

EPA violations include exceeding Maximum Contaminant Levels (MCLs), failing to treat water properly (treatment technique violations), and not testing or reporting on schedule (monitoring violations). Health-based violations are the most serious.

Does a high violation count mean the water is unsafe now?

Not necessarily. Many violations are historical or monitoring-related. However, a pattern of repeated violations indicates systemic issues with water system management or infrastructure.

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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