SAN JOAQUIN COUNTY - THORNTON

STOCKTON, CA · ~964 people served

Check your exact address → STOCKTON overview

100

Excellent

PurityRadar safety score

PWSID

CA3910009

State

California

City

STOCKTON

Population served

964

Primary source

Groundwater

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

No PFAS detections are on record for this system from EPA’s UCMR5 monitoring (2023–25). Absence of a detection isn’t a guarantee — not every system was sampled, and this dataset doesn’t cover other contaminants.

Violations & enforcement

Violations on record

Unaddressed

Health-based

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Aug 2009. Official EPA record →

Monitoring & reporting · Total coliform began Jul 2009 Resolved

Monitoring & reporting · Total coliform began Jan 2004 Resolved

Monitoring & reporting · Total coliform began Jan 1994 Resolved

Recent enforcement actions

State action · SFL Aug 2009
State action · SOX Aug 2009
State action · SFL Jan 2004
State action · SOX Jan 2004
State action · SOX Feb 1994
State action · SOX Feb 1994

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

Arsenic

1 station · latest Mar 2020

9.9 · max 9.9 ug/l · 1

Fluoride

1 station · latest Mar 2020

0.12 · max 0.12 mg/l · 1

Lead

1 station · latest Mar 2020

0.041 · max 0.041 ug/l · 1

Manganese

1 station · latest Mar 2020

109 · max 109 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 CA3910009 — 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.