COUNTY REPORT WI

Dane County, Wisconsin

58 ZIP codes · Avg score 62/100 · Grade C · Updated 2026-06-03

Water safety in Dane County is uneven — some of its 58 ZIP codes meet standards cleanly while others carry documented violations.

How Dane County Compares

Dane County62/100
Wisconsin avg66/100
National avg68/100

How Dane County Compares

C
County Grade
62/100
Avg Safety Score
58
ZIP Codes
44
Water Systems

Dane County scores 4 points below the Wisconsin state average (66/100) and 6 points below the national average (68/100).

Data: EPA SDWIS Last verified: 2026-06-03

C
County Grade
62
Avg Safety Score
58
ZIP Codes
Best ZIP: 53521 (70/100)
Lowest ZIP: 53532 (45/100)
$373K
Median Home Value
$2,522
Avg Remediation (68% of home value)

ZIP Code Risk Map

Water Quality Map: Dane 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: 10.2 (asthma 9.9%, diabetes 8.2%)

Estimated additional annual cost per homeowner: $566, driven primarily by flood

Infrastructure: 0.357% avg pipe failure probability, 21% of ZIPs at high risk

55% of homes built before 1978 (lead paint era)

Violation History (2021–2024)

↑ Worsening trend

EPA violation counts by year across Dane County water systems. Health-based shown in red, total in blue.

2021
1 (1 health)
2022
1 (1 health)
2023
40 (40 health)
2024
97 (97 health)

Peak year: 2024 with 97 violations. Past 5 years: 139 total (139 health-based). Health-based violations are rising versus the prior 2-year window — worth closer monitoring.

Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.

County Health Indicators vs National Average

Asthma 9.9% (national: 8.9%)
Diabetes 8.2% (national: 10.5%)
Obesity 32.4% (national: 32.4%)

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

Infrastructure Overview

1979
Median Build Year
55%
Pre-1978 Housing
36%
Pipe Failure Probability
21%
ZIPs at High Infra Risk
Low
Lead Pipe Risk

Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.

Compound Risk Breakdown

Estimated additional annual cost per homeowner: $566

Flood $241/yr
Energy Code Gap $169/yr
Underground Tanks $80/yr

Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).

Housing Age Distribution

251,845 housing units in Dane County

Pre-1940 11%
1940–1959 11%
1960–1979 24%
1980–1999 26%
2000+ 28%

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 Dane County

$373K
Median Home Value
$2,522
Est. Remediation Cost
0.7%
of Home Value
Remediation as % of home value low burden

Remediation costs are relatively manageable for most homeowners in Dane 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 Dane County residents

Asthma 9.9% (US avg: 8.9%)
Diabetes 8.2% (US avg: 11%)
Obesity 32.4% (US avg: 32.4%)

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

Water Systems with Most Violations

Top 5 systems in Dane County ranked by EPA violation count.

# Water System Population Violations
1 Madison Water Utility 272,000 430
2 Mendota Mental Health Inst 2,787 399
3 Waupun Correctional Inst 3,706 385
4 Fox Lake Correctional Institution 1,850 385
5 Shorewood Hills Waterworks 1,670 385

44 total water systems serve Dane County.

All ZIP Codes in Dane County

58 ZIP codes tracked in Dane County.

# ZIP Code City Safety Score Grade Violations Home Value
1 53521 Brooklyn 70 B 0 $366K
2 53529 Dane 70 B 1 $374K
3 53558 Mc Farland 70 B 0 $378K
4 53559 Marshall 70 B 0 $281K
5 53572 Mount Horeb 70 B 0 $382K
6 53517 Blue Mounds 69 C 3 $411K
7 53527 Cottage Grove 69 C 2 (1 health) $403K
8 53589 Stoughton 69 C 5 (1 health) $318K
9 53593 Verona 69 C 2 (1 health) $465K
10 53598 Windsor 69 C 0 $373K
11 53508 Belleville 66 C 2 (1 health) $331K
12 53571 Morrisonville 66 C 0
13 53596 Sun Prairie 65 C 3 (1 health)
14 53515 Black Earth 64 C 2 (1 health) $336K
15 53531 Deerfield 64 C 5 $334K
16 53560 Mazomanie 64 C 2 $329K
17 53590 Sun Prairie 64 C 3 (1 health) $355K
18 53705 Madison 64 C 11 (3 health) $447K
19 53714 Madison 64 C 11 (3 health) $275K
20 53715 Madison 64 C 11 (3 health) $436K
21 53717 Madison 64 C 11 (3 health) $405K
22 53719 Madison 64 C 11 (3 health) $349K
23 53562 Middleton 63 C 6 (2 health) $496K
24 53575 Oregon 63 C 20 (2 health) $385K
25 53528 Cross Plains 60 C 4 $425K
26 53597 Waunakee 60 C 14 $463K
27 53701 Madison 59 C 11 (3 health)
28 53702 Madison 59 C 11 (3 health)
29 53703 Madison 59 C 11 (3 health) $472K
30 53704 Madison 59 C 11 (3 health) $289K
31 53706 Madison 59 C 11 (3 health)
32 53707 Madison 59 C 11 (3 health)
33 53708 Madison 59 C 11 (3 health)
34 53711 Madison 59 C 11 (3 health) $388K
35 53713 Madison 59 C 11 (3 health) $259K
36 53716 Madison 59 C 11 (3 health) $325K
37 53718 Madison 59 C 11 (3 health) $329K
38 53725 Madison 59 C 11 (3 health)
39 53726 Madison 59 C 11 (3 health) $601K
40 53744 Madison 59 C 11 (3 health)
41 53774 Madison 59 C 11 (3 health)
42 53777 Madison 59 C 11 (3 health)
43 53778 Madison 59 C 11 (3 health)
44 53779 Madison 59 C 11 (3 health)
45 53782 Madison 59 C 11 (3 health)
46 53783 Madison 59 C 11 (3 health)
47 53784 Madison 59 C 11 (3 health)
48 53785 Madison 59 C 11 (3 health)
49 53786 Madison 59 C 11 (3 health)
50 53788 Madison 59 C 11 (3 health)
51 53789 Madison 59 C 11 (3 health)
52 53790 Madison 59 C 11 (3 health)
53 53791 Madison 59 C 11 (3 health)
54 53792 Madison 59 C 11 (3 health)
55 53793 Madison 59 C 11 (3 health)
56 53794 Madison 59 C 11 (3 health)
57 53583 Sauk City 57 C 8 $305K
58 53532 De Forest 45 D 0 $356K

Recommended Buyer Guides for Dane County

Filtered against federal data, fitted to local risks.

Overview

Dane County in Wisconsin covers 58 ZIP codes with an average Home Safety Score of C (62/100).

51 of 58 ZIP codes have recorded EPA violations. 116 health-based violations have been documented.

← Back to Wisconsin water quality report

Data Sources

Updated daily.

Frequently Asked Questions

Is water safe in Dane County?
Dane 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 Dane County?
Dane County is served by 44 public water systems that supply drinking water to residents across 58 ZIP codes.
What is the biggest environmental risk in Dane County?
The primary environmental risk factor in Dane County is flood. This contributes to an estimated additional annual cost of $566 per homeowner.
How old are homes in Dane County?
The median home build year in Dane County is 1979. 55% of homes were built before 1978, which means they may contain lead-based paint and older plumbing materials.
How does Dane County compare to Wisconsin?
Dane County has an average water safety score of 62/100, which is below the Wisconsin state average of 66/100.

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