Water Quality in San Antonio, TX: 337 Violations Recorded for Mapped Water Systems
36 water systems · 60 directly mapped ZIP records
Available EPA records report 337 violations across 60 directly mapped ZIP records with known counts for San Antonio. This is compliance evidence, not a property-level tap-water verdict.
Data: EPA Safe Drinking Water Information System (SDWIS)
Water Quality by ZIP Code in San Antonio
This table shows typed EPA water evidence only. Missing violation counts are displayed as N/A, not zero.
| ZIP Code | Violations | Health | |
|---|---|---|---|
| 78266 | 169 | 58 | View report → |
| 78245 | 55 | 13 | View report → |
| 78238 | 43 | 0 | View report → |
| 78240 | 43 | 0 | View report → |
| 78250 | 43 | 0 | View report → |
| 78264 | 31 | 12 | View report → |
| 78224 | 30 | 12 | View report → |
| 78252 | 30 | 12 | View report → |
| 78249 | 24 | 5 | View report → |
| 78219 | 11 | 1 | View report → |
| 78223 | 10 | 0 | View report → |
| 78253 | 10 | 1 | View report → |
| 78209 | 8 | 2 | View report → |
| 78213 | 8 | 4 | View report → |
| 78230 | 8 | 4 | View report → |
Water Quality Overview
San Antonio, Texas has directly mapped EPA water-system data for 60 ZIP codes. This page reports typed compliance facts and does not relabel the multi-source Home Safety Score as a drinking-water grade.
The available EPA records report 337 violations, including 80 health-based violations across 60 directly mapped ZIP records with reported counts.
Lead Levels
The average of the reported 90th-percentile lead results across the ZIP codes of San Antonio is 0.0017 mg/L; the EPA action level of 0.015 mg/L applies to a water system's own 90th-percentile result and is not a safety threshold (EPA's health goal for lead is zero). No exceedances appear among the 60 ZIP records with known lead status.
With 49% of homes built before 1986, San Antonio has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Water Systems Serving San Antonio
San Antonio is served by 36 community water systems regulated under the Safe Drinking Water Act. About 1,860,461 people live in the area (86 ZIP codes, Census); this is not the systems' reported service population.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
EPA records list enforcement actions against water systems serving San Antonio. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in San Antonio
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels and violation history
Request your CCR - your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test - certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration - NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories - monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in San Antonio Water Systems
The following contaminants have been detected or caused violations across San Antonio's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Public Notice Rule | Reporting | N/A | 108 | 16 | No |
| Interim Enhanced Surface Water Treatment Rule | Treatment Technique | N/A | 53 | 1 | No |
| Gross Alpha (excl. radon and uranium) | Radionuclides | 15 pCi/L | 48 | 4 | Yes |
| Chlorine | Disinfectant | 4 mg/L (MRDL) | 35 | 9 | No |
| Consumer Confidence Rule | Reporting | N/A | 28 | 16 | No |
| Lead and Copper Rule | Treatment Technique | N/A | 27 | 16 | Yes |
| Lead and Copper Rule Revisions | Treatment Technique | N/A | 26 | 16 | Yes |
| E. coli | Microbiological | N/A | 18 | 12 | No |
| Asbestos | Inorganic | 7 MFL | 16 | 4 | Yes |
| 1,2,4-Trichlorobenzene | Organic | N/A | 6 | 3 | No |
| cis-1,2-Dichloroethylene | Organic | N/A | 6 | 3 | No |
| Xylenes, Total | Organic | N/A | 6 | 3 | No |
| Dichloromethane | Organic | N/A | 6 | 3 | No |
| o-Dichlorobenzene | Organic | N/A | 6 | 3 | No |
| p-Dichlorobenzene | Organic | N/A | 6 | 3 | No |
The standard column shows the EPA Maximum Contaminant Level (MCL) except for lead and copper, whose value is an action level that triggers corrective steps and is not an MCL. Health-based violations are MCL, MRDL and treatment-technique violations.
Violation Trend Over Time
Year-by-year health-based EPA violations recorded for water systems serving San Antonio (this history covers health-based records only):
| Year | Health-based violations |
|---|---|
| 2021 | 22 |
| 2022 | 28 |
| 2023 | 23 |
| 2024 | 28 |
| 2025 | 16 |
| 2026 | 1 |
Health-based violations have decreased from 22 in 2021 to 1 in 2026, indicating improving compliance.
EPA Enforcement History
The EPA and state regulators have taken enforcement actions against water systems serving San Antonio. Recent actions:
| Date | Action Type |
|---|---|
| 2026-06-19 | State Informal Action |
| 2026-06-16 | State Informal Action |
| 2026-06-12 | State Informal Enforcement |
| 2026-06-03 | State Order Extension |
| 2026-06-03 | State Informal Action |
| 2026-05-29 | State Informal Action |
| 2026-05-27 | State Informal Action |
| 2026-05-19 | State Informal Action |
| 2026-05-12 | State Informal Action |
| 2026-05-11 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2026-06-19.
San Antonio vs. Nearby Texas Cities
How San Antonio's water quality compares to similar cities in Texas:
| City | Direct EPA ZIPs | Violations | Systems | Population |
|---|---|---|---|---|
| San Antonio | 60 | 337 | 36 | 1,860,461 |
| Dallas | 49 | 30 | 18 | 1,372,181 |
| Austin | 44 | 138 | 46 | 1,157,348 |
| Fort Worth | 32 | 334 | 37 | 982,017 |
Water Quality by ZIP Code in San Antonio
EPA coverage and recorded violations can differ across San Antonio's ZIP codes. Missing counts are shown as unavailable, not zero:
| ZIP Code | Violations | Health-Based |
|---|---|---|
| 78266 | 169 | 58 |
| 78245 | 55 | 13 |
| 78238 | 43 | 0 |
| 78240 | 43 | 0 |
| 78250 | 43 | 0 |
| 78264 | 31 | 12 |
| 78224 | 30 | 12 |
| 78252 | 30 | 12 |
| 78249 | 24 | 5 |
| 78219 | 11 | 1 |
| 78223 | 10 | 0 |
| 78253 | 10 | 1 |
| 78209 | 8 | 2 |
| 78213 | 8 | 4 |
| 78230 | 8 | 4 |
Common Questions About San Antonio Water
These are the most common questions residents search for about water quality in San Antonio, Texas:
Is San Antonio water hard or soft? Water hardness varies by source. San Antonio's 36 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink San Antonio tap water? City-level EPA records cannot determine safety at a specific tap. The measured subset contains 80 health-based violations; check the affected utility record and consider certified testing.
What is the best water filter for San Antonio? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
San Antonio vs. Texas Average
Understanding how San Antonio compares to the broader Texas average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below - water quality can vary significantly even within San Antonio.
ZIP Codes in San Antonio
San Antonio spans 86 ZIP codes. EPA water-system coverage is available for 60 directly mapped ZIP codes. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Source reporting periods vary. See each cited source for its publication schedule.