GSWC-SAN DIMAS

SAN DIMAS, CA · ~56,538 people served

Check your exact address → SAN DIMAS overview

Excellent

PurityRadar safety score

PWSID

CA1910142

State

California

City

SAN DIMAS

Population served

56,538

Primary source

SWP

Score history

▼ 11 points — the score moved from 100 to 89 on Jun 18, 2026, as newly published EPA data was incorporated.

Jun 18, 2026 · score 100 Jun 18, 2026 · score 89

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 Feb 2025). Levels in parts per trillion (ppt).

PFOS

Perfluorooctanesulfonic acid

4.5 ppt

limit 4 ppt

Above EPA limit · 1.1×

Lithium

57,000 ppt

limit —

No federal limit

Violations & enforcement

Violations on record

Unaddressed

Health-based

Enforcement actions

From EPA ECHO (SDWIS), most recent enforcement Jan 1998. Official EPA record →

Max contaminant level (MCL) · Nitrate health-based began Sep 1997 Resolved

Max contaminant level (MCL) · Nitrate health-based began Dec 1995 Resolved

Recent enforcement actions

EPA/federal action · EOX Jan 1998
State action · SFJ Dec 1997
State action · SOX Dec 1997
State action · SFJ Mar 1996
State action · SOX Mar 1996

This profile is built from EPA public records for system CA1910142 — 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.