Fresno Water Quality Summary
City of Fresno supplies drinking water to about 545,716 people in Fresno, California, and draws from surface water (rivers, lakes, or reservoirs), which requires fuller treatment for runoff, sediment, and microbial risk. On the IsWaterSafe scale it earns an excellent Water Safety Score of 94 out of 100 (Grade A), a composite of its EPA SDWIS violation and contaminant record.
EPA SDWIS shows no health-based or monitoring violations on record for City of Fresno, though 2 enforcement actions are logged in its history.
Across the single substance sampled, none exceeded its EPA limit. Nitrate sits highest relative to its ceiling, detected at 5 ppm against an MCL of 10 ppm (sampled January 2016) — within the legal limit.
The most recent documented episode is a health-based violation involving Nitrate, beginning January 2016 and marked resolved July 2017.
Track City of Fresno
Subscribe for WaterSafety updates by email. No spam, unsubscribe anytime.
Detected Contaminants
| Contaminant | Detected Level | MCL (Limit) | Status | Sample Date |
|---|---|---|---|---|
| Nitrate | 5 ppm | 10 ppm | Within Limit | Jan 1, 2016 |
Violation History
Frequently Asked Questions
City of Fresno has a Water Safety Score of A (94/100). The system serves 545,716 people and has 0 health violations on record. Check the contaminant table above for specific detected substances.
City of Fresno 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.