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Water system · PWSID CA3510001

HOLLISTER, CITY OF

HOLLISTER, CA · ~26,017 people served

Check your exact address → HOLLISTER overview
100
Excellent
PurityRadar safety score

PWSID

CA3510001

State

California

City

HOLLISTER

Population served

26,017

Primary source

SWP

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).

Lithium

22,000 ppt

limit —

No federal limit

Violations & enforcement

15

Violations on record

0

Unaddressed

6

Health-based

22

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Jan 2023. Official EPA record →

Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Jul 2022 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Oct 2018 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Jul 2018 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Jan 2016 Resolved
Monitoring & reporting · Total coliform began Oct 2015 Resolved
Max contaminant level (MCL) · Total trihalomethanes (TTHM) health-based began Oct 2015 Resolved
Monitoring & reporting · Nitrate began Apr 2010 Resolved
Monitoring & reporting · Nitrate began Jan 2010 Resolved
Monitoring & reporting · Combined radium-226/228 began Jan 2002 Resolved
Monitoring & reporting · Total coliform began Mar 2000 Resolved
Monitoring & reporting · Nitrate began Jan 1999 Resolved
Max contaminant level (MCL) · Nitrate health-based began Jan 1999 Resolved

Recent enforcement actions

  • State action · SOX Jan 2023
  • State action · SFL Oct 2022
  • State action · SOX Jan 2019
  • State action · SFL Jan 2019
  • State action · SOX Sep 2016
  • State action · SFL Apr 2016
  • State action · SOX Nov 2015
  • State action · SIA Nov 2015

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

Nitrate

1 station · latest Oct 2022

55.4 · max 55.4 mg/l as N · 2

Arsenic

1 station · latest Oct 2022

0.99 · max 0.99 ug/l · 1

Uranium

1 station · latest Oct 2022

19.2 · max 19.2 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 CA3510001 — 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.