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San Marcos, TX Tap Water Quality 2026

Water quality report for San Marcos, TX — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at San Marcos's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: City Of San Marcos PWSID: TX1050001 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 1.63 ppb, 11% of the action level and no violations are open. No PFAS was detected.

A

San Marcos earns an A for water quality

Graded on violations, lead, and PFAS, with state inspection findings.

Lead: 1.63 ppb — 11% of the federal action level
PFAS tested, none detected
5 violations since 2015, 2 health-based
No violations currently open
San Marcos's lead level vs. all Texas community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 1.63 ppb — 11% of the federal action level
✓ Lower lead than 49% of Texas utilities
Population Served
60494
~42746 connections
Water Source
Surface water
Drawn from surface water — SDWIS source code SW
Active Violations
0
5 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
11% of EPA action level
1.63 ppb
Action level: 15 ppb
The 90th-percentile lead result is 1.63 ppb, 11% of the 15 ppb federal action level. The action level is a treatment trigger, not a legal maximum, and it is measured across sampled taps rather than at any single home.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
TTHM MCL EXCEEDANCE 0.081 MG/L 0.080 mg/L 2025 Resolved
Chlorite MONITORING AND REPORTING — 1.0 mg/L 2021 Resolved
Public Notice OTHER — — 2016 Resolved
TTHM MCL EXCEEDANCE 0.082 MG/L 0.080 mg/L 2016 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2015 Resolved
Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

5 violations are on record since 2015, of which 2 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility City Of San Marcos
PWSID TX1050001
Water source Surface water — Drawn from surface water — SDWIS source code SW
Population served 60,494
Service connections 42,746
Systems serving this area 6
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is San Marcos tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 1.63 ppb, 11% of the action level.
Does San Marcos water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to San Marcos? ▼
City Of San Marcos (PWSID TX1050001), one of 6 systems serving this area. Surface water. Drawn from surface water — SDWIS source code SW
When was this system last inspected? ▼
It was last inspected on 2023-06-23. No significant deficiencies were recorded.

What Should San Marcos Residents Do?

1
Read your annual water report
Your supplier publishes a Consumer Confidence Report each July covering the prior year.
2
Check for a lead service line
Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.
3
Flush before drinking
If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

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