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Water system · PWSID TX1050001

CITY OF SAN MARCOS

SAN MARCOS, TX · ~72,970 people served

Check your exact address → SAN MARCOS overview
100
Excellent
PurityRadar safety score

PWSID

TX1050001

State

Texas

City

SAN MARCOS

Population served

72,970

Primary source

Surface water

Score history

No change since tracking began Jun 18, 2026.

Jun 18, 2026 · score 100 Jun 18, 2026 · score 100

2 score updates logged since tracking began Jun 18, 2026. Each future EPA re-score adds a point.

PFAS & contaminant readings

Latest detections from EPA’s UCMR5 monitoring (through Aug 2024). Levels in parts per trillion (ppt).

PFHxS

Perfluorohexanesulfonic acid

3.4 ppt

limit 10 ppt

Below EPA limit

Lithium

11,300 ppt

limit —

No federal limit

PFBA

8.8 ppt

limit —

No federal limit

PFPeA

3.7 ppt

limit —

No federal limit

Violations & enforcement

10

Violations on record

0

Unaddressed

6

Health-based

27

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement May 2022. Official EPA record →

Monitoring & reporting · EPA contaminant 1009 began Feb 2021 Resolved
Other · EPA contaminant 7500 began May 2016 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Jan 2016 Resolved
Monitoring & reporting · Lead & Copper Rule began Dec 2015 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Jul 2014 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Apr 2014 Resolved
Other · EPA contaminant 7500 began Mar 2014 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Jan 2014 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Oct 2013 Resolved
Treatment technique · EPA contaminant 0200 health-based began Jan 2003 Resolved

Recent enforcement actions

  • State action · SIF May 2022
  • State action · SIE May 2021
  • State action · SIA May 2021
  • State action · SOX May 2021
  • State action · SOX Jun 2016
  • State action · SOX May 2016
  • State action · SIF May 2016
  • State action · SIA Apr 2016

Area water-quality monitoring

Environmental monitoring (rivers, wells, intakes) recorded in this system’s service area in the EPA/USGS Water Quality Portal since 2018 — source/ambient water, not finished tap water. Context for the watershed, not a reading from your tap.

ContaminantMedian · max · samples

Fluoride

1 station · latest Feb 2026

0.165 · max 0.238 mg/L · 15

Nitrate

1 station · latest Oct 2022

1.8 · max 1.8 mg/l as N · 2

Arsenic

1 station · latest Oct 2022

0.35 · max 0.35 ug/l · 1

Copper

1 station · latest Oct 2022

3.3 · max 3.3 ug/l · 1

Lead

1 station · latest Oct 2022

0.195 · max 0.195 ug/l · 1

Uranium

1 station · latest Oct 2022

0.753 · max 0.753 ug/l · 1

Source: Water Quality Portal (EPA/USGS/state agencies). Values are as-reported and aren’t health thresholds.

This profile is built from EPA public records for system TX1050001 — SDWIS violations and UCMR5 PFAS sampling. The score is system-level and can’t account for your home’s plumbing (older pipes can add lead at the tap). For health decisions, check your exact address, read the utility’s Consumer Confidence Report, and confirm with your provider.