Rock County, Wisconsin
16 ZIP codes · Avg score 65/100 · Grade C · Updated
ZipCheckup grade for Rock County: C.
A mixed picture - some signals here are worth your attention.
Within Rock County, 16 tracked ZIP codes reveal moderate water quality - national standards are generally met, with some documented exceptions.
How Rock County Compares
How Rock County Compares
Rock County scores 5 points below the Wisconsin state average (70/100) and 8 points below the national average (73/100).
Data: ZipCheckup Home Safety Score model 4.0.0; EPA SDWIS, UCMR 5, EPA radon zones, EPA AirData Last verified:
ZIP Code Risk Map
Water Quality Map: Rock County, Wisconsin
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.4 (asthma 11.2%, diabetes 12.3%)
Estimated additional annual cost per homeowner: $1,434, driven primarily by flood
74.8% of homes built before 1978 (lead paint era)
Violation History (2022–2024)
→ Stable trendEPA violation counts by year across Rock County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 12 violations. Past 5 years: 15 total (15 health-based).
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Modeled area-level indicator, not a failure probability. Sources: Census ACS housing age, EPA DWINS infrastructure needs, EPA SDWIS violations, and EPA lead indicators.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $1,434
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
73,090 housing units in Rock County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Rock County
Remediation costs are relatively manageable for most homeowners in Rock County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Rock County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water systems serving Rock County
8 community water systems serving Rock County.
- C
- C
- C
- C
- C
Show all 8 water systems
- C
- C
13 total water systems serve Rock County.
Systems with the most violations in Rock County
5 water systems with recorded EPA violations.
- C
- C
- C
- C
- C
All ZIP Codes in Rock County
16 ZIP codes tracked in Rock County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 53546 | Janesville | 67 | C | 0 | $220K |
| 2 | 53563 | Milton | 67 | C | 0 | $271K |
| 3 | 53511 | Beloit | 66 | C | 1 | $160K |
| 4 | 53525 | Clinton | 66 | C | 1 | $229K |
| 5 | 53545 | Janesville | 66 | C | 3 | $204K |
| 6 | 53548 | Janesville | 65 | C | 4 (1 health) | $227K |
| 7 | 53534 | Edgerton | 64 | C | 5 (1 health) | $280K |
| 8 | 53536 | Evansville | 60 | C | 13 (3 health) | $275K |
| 9 | 53501 | Afton | — | — | 0 | — |
| 10 | 53505 | Avalon | — | — | $258K | |
| 11 | 53512 | Beloit | — | — | — | |
| 12 | 53520 | Brodhead | — | — | 2 (2 health) | $212K |
| 13 | 53537 | Footville | — | — | $147K | |
| 14 | 53542 | Hanover | — | — | — | |
| 15 | 53547 | Janesville | — | — | — | |
| 16 | 53576 | Orfordville | — | — | 1 (1 health) | $207K |
Recommended Buyer Guides for Rock County
Federal and certification sources drive the ordering: EPA monitoring data, NSF certifications, FEMA flood maps, and CDC lead guidance - guides surface only when county data warrants them.
- Best Lead Paint Test Kits — 74.8% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for Rock County, Wisconsin
Overview
Rock County in Wisconsin covers 16 tracked ZIP records with an average Home Safety Score of C (65/100) across 8 scored records.
8 of 11 ZIP codes with a reported violation count in the available EPA record have recorded EPA violations. 5 health-based violations appear in the available health breakdown.
← Back to Wisconsin Home Safety Profile
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- PFAS screening: EPA UCMR 5
- Radon zones: EPA Map of Radon Zones
- Air quality: EPA AirData annual AQI
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Reporting periods vary by source. Missing data is shown as unavailable, not as zero.