San Antonio Water System
San Antonio, Texas · PWSID: TX0150018
San Antonio Water Quality Summary
San Antonio Water System supplies drinking water to about 2,113,151 people in San Antonio, Texas, 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 a good Water Safety Score of 80 out of 100 (Grade B), a composite of its EPA SDWIS violation and contaminant record.
EPA SDWIS shows no health-based or monitoring violations on record for San Antonio Water System, though 11 enforcement actions are logged in its history.
Across the 2 substances sampled, none exceeded its EPA limit. Total Coliform sits highest relative to its ceiling, detected at 2.5 % positive against an MCL of 5 % positive (sampled February 2016) — within the legal limit.
The most recent documented episode is a treatment technique violation involving Total Coliform, beginning February 2016 and marked resolved August 2016.
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Detected Contaminants
| Contaminant | Detected Level | MCL (Limit) | Status | Sample Date |
|---|---|---|---|---|
| Total Coliform | 2.5 % positive | 5 % positive | Within Limit | Feb 1, 2016 |
| E. coli (RTCR) | 0 presence | 0 presence | Within Limit | Jun 10, 2016 |
Violation History
Frequently Asked Questions
San Antonio Water System has a Water Safety Score of B (80/100). The system serves 2,113,151 people and has 0 health violations on record. Check the contaminant table above for specific detected substances.
San Antonio Water System 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.