COUNTY REPORT WI

Rock County, Wisconsin

16 ZIP codes · Avg score 65/100 · Grade C

ZipCheckup grade for Rock County: C.

A mixed picture - some signals here are worth your attention.

Somewhere in the middle: that is where the composite score for Rock County lands, across 16 tracked ZIP codes.

How Rock County Compares

Rock County65/100
Wisconsin avg70/100
National avg73/100

How Rock County Compares

C
County Grade
65/100
Avg Safety Score
16
ZIP Codes
13
Water Systems

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

C
County Grade
65
Avg Safety Score
16
ZIP Codes
Best ZIP: 53546 (67/100)
Lowest ZIP: 53536 (60/100)
$223K
Median Home Value
$383
Avg Remediation (0.17% of home value)

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.

A B C D F

Key Risk Factors

Health risk index: 13.4 (asthma 11.2%, diabetes 12.3%)

Modeled additional annual cost estimate per homeowner: $1,226, largest modeled factor: Flood

66% of homes built before 1980 (lead paint was banned for residential use in 1978)

County Health Indicators vs National Average

Asthma 11.2% (national: 8.9%)
Diabetes 12.3% (national: 10.5%)
Obesity 41.9% (national: 32.4%)

Black markers indicate national averages. Source: CDC PLACES, Census ACS.

Infrastructure Overview

1964
Median Build Year
66%
Pre-1980 Housing
45/100
Infrastructure Stress Indicator
67%
ZIPs with High Infrastructure Stress
High
Lead Pipe Risk

Modeled area-level indicator, not a failure probability. Sources: Census ACS housing age, EPA DWINSA infrastructure needs, EPA SDWIS violations, and EPA lead indicators.

Compound Risk Breakdown

Estimated additional annual cost per homeowner: $1,226

Flood $800/yr
Energy Code Gap $436/yr
Water / Lead $395/yr

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

Pre-1940 20%
1940–1959 18%
1960–1979 28%
1980–1999 20%
2000+ 14%

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

$223K
Median Home Value
$383
Est. Remediation Cost
0.2%
of Home Value
Remediation as % of home value low burden

Modeled remediation costs in Rock County can be compared with the median property value; actual costs vary by property.

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

Asthma 11.2% (US avg: 8.9%)
Diabetes 12.3% (US avg: 11%)
Obesity 41.9% (US avg: 32.4%)

Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.

Water systems mapped to Rock County ZIP codes

8 community water systems mapped to Rock County ZIP codes; EPA may list more systems serving the county.

Show all 8 water systems

13 water systems mapped to Rock County ZIP codes in our data; EPA may list more systems serving the county.

Systems with the most violations in Rock County

5 water systems with violations in EPA records.

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

When no specific signal shows up in the records, the list falls back to general water testing and filtration guides rather than staying empty.

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

Reporting periods vary by source. Missing data is shown as unavailable, not as zero.

Frequently Asked Questions

Is water safe in Rock County?
Rock County receives a grade of C. Some ZIP codes have recorded violations and residents in affected areas may want to test their water.
How many water systems serve Rock County?
We map 13 public water systems to 16 ZIP codes in our data for Rock County. EPA may list more systems serving the county, so this is not a full count.
What is the biggest environmental risk in Rock County?
In ZipCheckup's cost model, the factor with the largest estimated average annual cost in Rock County is flood. Across all modeled risk factors, the estimated average additional annual cost is $1,226 per homeowner; actual costs vary by home.
How old are homes in Rock County?
The median home build year in Rock County is 1964. 66% of homes were built before 1980; homes built before 1978 may contain lead-based paint, and older homes may have older plumbing materials.
How does Rock County compare to Wisconsin?
Rock County has an average Home Safety Score of 65/100 under model 4.0.0, which is below the Wisconsin state average of 70/100.

How to cite this page

APA ZipCheckup. (2026). Rock County, WI: HSS 65/100; 5 Health Violations. https://zipcheckup.com/county/wisconsin/rock/
BibTeX
@misc{zipcheckup-county-wisconsin-rock,
  author = {{ZipCheckup}},
  title  = {{Rock County, WI: HSS 65/100; 5 Health Violations}},
  year   = {2026},
  url    = {https://zipcheckup.com/county/wisconsin/rock/}
}

Page version: October 2026.

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