Madison Water Utility
Madison, Wisconsin · PWSID: WI1130224
Madison Water Quality Summary
Madison Water Utility supplies drinking water to about 272,000 people in Madison, Wisconsin, and draws from ground water (wells or aquifers), which is naturally filtered but can carry minerals and contaminants from the surrounding geology. On the IsWaterSafe scale it earns a good Water Safety Score of 87 out of 100 (Grade B), a composite of its EPA SDWIS violation and contaminant record.
EPA records show 1 health-based violation for this system. A health-based violation means a contaminant exceeded its legal EPA limit, the most serious category in the Safe Drinking Water Act. The system has 1 enforcement action on file in response.
Across the single substance sampled, none exceeded its EPA limit. E. coli (RTCR) sits highest relative to its ceiling, detected at 0 presence against an MCL of 0 presence (sampled October 2024) — within the legal limit.
The most pressing open issue is a reporting violation involving E. coli (RTCR), beginning October 2024 and still open in EPA records.
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Detected Contaminants
| Contaminant | Detected Level | MCL (Limit) | Status | Sample Date |
|---|---|---|---|---|
| E. coli (RTCR) | 0 presence | 0 presence | Within Limit | Oct 17, 2024 |
Violation History
Frequently Asked Questions
Madison Water Utility has a Water Safety Score of B (87/100). The system serves 272,000 people and has 1 health violation on record. Check the contaminant table above for specific detected substances.
Madison Water Utility has 0 contaminant exceedances above EPA health guidelines. See the full contaminant detection table above for all tested substances and their levels relative to legal limits and health guidelines.
The Water Safety Score (0-100, grades A through F) is based on contaminant levels relative to legal limits, health guideline exceedances, violation history, and enforcement actions. Higher scores indicate fewer concerns.
If your water system has violations, request the Consumer Confidence Report from your utility, consider getting an independent water test from a certified lab, and look into certified water filters for specific contaminants of concern. For lead, run cold water for 30 seconds before drinking.
Water quality data sourced from EPA's Safe Drinking Water Information System (SDWIS). Safety scores are calculated based on contaminant levels, violations, and enforcement history. This is not a substitute for your utility's official Consumer Confidence Report.
Source: EPA Ground Water and Drinking Water, 2026.