Sauk County, Wisconsin
13 ZIP codes · Avg score 74/100 · Grade B · Updated 2026-06-03
Sauk County's tap water quality puts it in the upper tier nationally; the 13 ZIP codes here record few health-based violations.
How Sauk County Compares
How Sauk County Compares
Sauk County scores 8 points above the Wisconsin state average (66/100) and 6 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Sauk County, Wisconsin
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.6 (asthma 10.8%, diabetes 12.3%)
Estimated additional annual cost per homeowner: $969, driven primarily by flood
Infrastructure: 0.373% avg pipe failure probability, 23% of ZIPs at high risk
59.8% of homes built before 1978 (lead paint era)
Violation History (2023–2024)
→ Stable trendEPA violation counts by year across Sauk County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 8 violations. Past 5 years: 9 total (9 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
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $969
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
25,366 housing units in Sauk 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 Sauk County
Remediation costs are relatively manageable for most homeowners in Sauk 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 Sauk County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Sauk County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | La Valle Waterworks | 365 | 10 |
| 2 | Ironton Waterworks | 253 | 10 |
| 3 | Reedsburg Waterworks | 9,984 | 10 |
| 4 | Equinox Rei Llc Dellwood Estates | 70 | 10 |
| 5 | Dell Creek Estates | 50 | 10 |
27 total water systems serve Sauk County.
All ZIP Codes in Sauk County
13 ZIP codes tracked in Sauk County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 53943 | Loganville | 83 | B | 0 | $231K |
| 2 | 53561 | Merrimac | 82 | B | 3 (1 health) | $407K |
| 3 | 53940 | Lake Delton | 82 | B | 2 | — |
| 4 | 53958 | Reedsburg | 81 | B | 5 | — |
| 5 | 53578 | Prairie Du Sac | 79 | B | 8 (3 health) | $334K |
| 6 | 53951 | North Freedom | 78 | B | 0 | $186K |
| 7 | 53961 | Rock Springs | 78 | B | 1 | $200K |
| 8 | 53577 | Plain | 77 | B | 9 (2 health) | $248K |
| 9 | 53941 | La Valle | 76 | B | 10 (2 health) | $253K |
| 10 | 53959 | Reedsburg | 71 | B | 5 | $241K |
| 11 | 53913 | Baraboo | 70 | B | 1 | $215K |
| 12 | 53937 | Hillpoint | 53 | D | 0 | $262K |
| 13 | 54441 | Hewitt | 53 | D | 0 | $207K |
Recommended Buyer Guides for Sauk County
Eight risk categories drive the selection — PFAS exceedance, lead above EPA action level, pre-1978 housing share, EPA Radon Zone 1, flood-top-risk, wildfire-top-risk, multi-contaminant load, and a baseline fallback — and each category maps to a specific buyer-guide track that surfaces when the county data hits its threshold for that hazard signal.
- Best Lead Paint Test Kits — 59.8% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- 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 Sauk County, Wisconsin
Overview
Sauk County in Wisconsin covers 13 ZIP codes with an average Home Safety Score of B (74/100).
9 of 13 ZIP codes have recorded EPA violations. 8 health-based violations have been documented.
← Back to Wisconsin water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.