Wisconsin — 4th District
119th Congress · 58 ZIP codes · Avg score 61/100 · Grade C · Updated 2026-06-03
Data: EPA SDWIS / Census 119th Congress Last verified: 2026-06-03
Top Contaminants
ZIP Codes in This District
58 ZIP codes tracked in Wisconsin's 4th District. Showing top 50 by safety score.
| # | ZIP Code | City | Safety Score | Grade | Violations |
|---|---|---|---|---|---|
| 1 | 53156 | Palmyra | 70 | B | 1 |
| 2 | 53178 | Sullivan | 70 | B | 0 |
| 3 | 53038 | Johnson Creek | 69 | C | 17 (1 health) |
| 4 | 53036 | Ixonia | 68 | C | 4 |
| 5 | 53201 | Milwaukee | 67 | C | 120 (2 health) |
| 6 | 53202 | Milwaukee | 67 | C | 120 (2 health) |
| 7 | 53203 | Milwaukee | 67 | C | 120 (2 health) |
| 8 | 53204 | Milwaukee | 67 | C | 120 (2 health) |
| 9 | 53205 | Milwaukee | 67 | C | 120 (2 health) |
| 10 | 53206 | Milwaukee | 67 | C | 120 (2 health) |
| 11 | 53207 | Milwaukee | 67 | C | 120 (2 health) |
| 12 | 53210 | Milwaukee | 67 | C | 120 (2 health) |
| 13 | 53212 | Milwaukee | 67 | C | 120 (2 health) |
| 14 | 53214 | Milwaukee | 67 | C | 120 (2 health) |
| 15 | 53219 | Milwaukee | 67 | C | 120 (2 health) |
| 16 | 53220 | Milwaukee | 67 | C | 120 (2 health) |
| 17 | 53228 | Milwaukee | 67 | C | 120 (2 health) |
| 18 | 53233 | Milwaukee | 67 | C | 120 (2 health) |
| 19 | 53089 | Sussex | 66 | C | 6 (1 health) |
| 20 | 53234 | Milwaukee | 63 | C | 120 (2 health) |
| 21 | 53237 | Milwaukee | 63 | C | 120 (2 health) |
| 22 | 53244 | Milwaukee | 63 | C | 120 (2 health) |
| 23 | 53259 | Milwaukee | 63 | C | 120 (2 health) |
| 24 | 53263 | Milwaukee | 63 | C | 120 (2 health) |
| 25 | 53267 | Milwaukee | 63 | C | 120 (2 health) |
| 26 | 53268 | Milwaukee | 63 | C | 120 (2 health) |
| 27 | 53274 | Milwaukee | 63 | C | 120 (2 health) |
| 28 | 53278 | Milwaukee | 63 | C | 120 (2 health) |
| 29 | 53288 | Milwaukee | 63 | C | 120 (2 health) |
| 30 | 53290 | Milwaukee | 63 | C | 120 (2 health) |
| 31 | 53293 | Milwaukee | 63 | C | 120 (2 health) |
| 32 | 53295 | Milwaukee | 63 | C | 120 (2 health) |
| 33 | 53018 | Delafield | 62 | C | 25 (5 health) |
| 34 | 53208 | Milwaukee | 62 | C | 120 (2 health) |
| 35 | 53211 | Milwaukee | 62 | C | 120 (2 health) |
| 36 | 53215 | Milwaukee | 62 | C | 120 (2 health) |
| 37 | 53221 | Milwaukee | 62 | C | 120 (2 health) |
| 38 | 53222 | Milwaukee | 62 | C | 120 (2 health) |
| 39 | 53224 | Milwaukee | 62 | C | 120 (2 health) |
| 40 | 53225 | Milwaukee | 62 | C | 120 (2 health) |
| 41 | 53226 | Milwaukee | 62 | C | 120 (2 health) |
| 42 | 53227 | Milwaukee | 62 | C | 120 (2 health) |
| 43 | 53551 | Lake Mills | 58 | C | 3 (1 health) |
| 44 | 53213 | Milwaukee | 57 | C | 120 (2 health) |
| 45 | 53216 | Milwaukee | 57 | C | 120 (2 health) |
| 46 | 53223 | Milwaukee | 57 | C | 120 (2 health) |
| 47 | 53003 | Ashippun | 53 | D | 0 |
| 48 | 53118 | Dousman | 53 | D | 24 (11 health) |
| 49 | 53066 | Oconomowoc | 52 | D | 7 |
| 50 | 53209 | Milwaukee | 52 | D | 120 (2 health) |
Overview
Wisconsin's 4th District serving an estimated 29,212,157 residents encompasses 58 ZIP codes tracked by ZipCheckup. The district's average Home Safety Score is C (61/100).
5160 EPA violations have been recorded across this district's water systems. 112 are health-based violations. About 93% of tracked ZIP codes have at least one violation.
Top Contaminants
The most frequently cited water quality issues in this district:
- Consumer Confidence Report Rule — 864 violations
- Lead and Copper Rule — 345 violations
- Stage 1 DBP Rule — 274 violations
- Surface Water Treatment Rule — 267 violations
- Stage 2 DBP Rule — 178 violations
Housing Context
Homes in this district were built on average around 1956 (~70 years old). Older homes may have lead pipes or solder — consider a water filter if your home predates 1986.
Lead Alert: 1 ZIP code in this district exceed the EPA action level for lead. Consider using a certified lead-removal filter.
Data Sources
- Water quality violations: EPA Safe Drinking Water Information System (SDWIS)
- Congressional district boundaries: U.S. Census Bureau, 119th Congress
- Housing age: U.S. Census Bureau American Community Survey
Updated daily. Data covers 58 ZIP codes in Wisconsin's 4th District.